* unexelf.c: Fix some 32-bit integer problems, notably when debugging.
Include <limits.h>, <stdbool.h>, <intprops.h>, <verify.h>. Verify that ElfW (Half) fits in int. (fatal): Use same signature as lisp.h. (UNEXELF_DEBUG): New macro, replacing DEBUG, so that people can configure and build with -DUNEXELF_DEBUG without worrying about other modules that use DEBUG. (DEBUG_LOG) [UNEXELF_DEBUG]: New macro. All debug code that prints possibly-wide integers now uses it instead of plain fprintf. (entry_address): New function, which avoids problems with 32-bit overflow on 64-bit hosts. (OLD_SECTION_H, NEW_SECTION_H, NEW_PROGRAM_H): Use it. (round_up): Don't assume the remainder fits in int. (find_section): Use bool for boolean. Simplify debug code. (unexec): Don't assume file sizes fit in int or size_t. Omit unnecessary trailing newline in 'fatal' format. Use strerror rather than outputting decimal error number. Remove unused code when emacs is not defined; this file relies on Emacs now. Don't assume e_phnum and e_shnum are positive.
This commit is contained in:
Paul Eggert
parent
dc4a2ee0ef
commit
5ee94506f6
2 changed files with 118 additions and 84 deletions
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@ -1,5 +1,26 @@
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2013-05-06 Paul Eggert <eggert@cs.ucla.edu>
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* unexelf.c: Fix some 32-bit integer problems, notably when debugging.
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Include <limits.h>, <stdbool.h>, <intprops.h>, <verify.h>.
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Verify that ElfW (Half) fits in int.
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(fatal): Use same signature as lisp.h.
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(UNEXELF_DEBUG): New macro, replacing DEBUG, so that people can
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configure and build with -DUNEXELF_DEBUG without worrying about
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other modules that use DEBUG.
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(DEBUG_LOG) [UNEXELF_DEBUG]: New macro. All debug code that prints
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possibly-wide integers now uses it instead of plain fprintf.
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(entry_address): New function, which avoids problems with 32-bit
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overflow on 64-bit hosts.
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(OLD_SECTION_H, NEW_SECTION_H, NEW_PROGRAM_H): Use it.
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(round_up): Don't assume the remainder fits in int.
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(find_section): Use bool for boolean. Simplify debug code.
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(unexec): Don't assume file sizes fit in int or size_t.
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Omit unnecessary trailing newline in 'fatal' format.
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Use strerror rather than outputting decimal error number.
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Remove unused code when emacs is not defined;
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this file relies on Emacs now.
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Don't assume e_phnum and e_shnum are positive.
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* regex.c: Fix problems when DEBUG is defined.
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(extract_number, extract_number_and_incr): Define regardless of
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whether DEBUG is defined; that's simpler and makes the code less
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181
src/unexelf.c
181
src/unexelf.c
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@ -388,16 +388,19 @@ raid:/nfs/raid/src/dist-18.56/src> dump -h temacs
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#include <config.h>
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#include <unexec.h>
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extern void fatal (const char *msgid, ...);
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extern _Noreturn void fatal (const char *, ...) ATTRIBUTE_FORMAT_PRINTF (1, 2);
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#include <sys/types.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <memory.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <sys/stat.h>
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#include <memory.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <fcntl.h>
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#if !defined (__NetBSD__) && !defined (__OpenBSD__)
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#include <elf.h>
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#endif /* not __NetBSD__ and not __OpenBSD__ */
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@ -519,6 +522,17 @@ typedef struct {
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# define ElfW(type) ElfExpandBitsW (ELFSIZE, type)
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#endif
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/* The code often converts ElfW (Half) values like e_shentsize to int;
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check that this doesn't lose information. */
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#include <intprops.h>
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#include <verify.h>
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verify ((! TYPE_SIGNED (ElfW (Half)) || INT_MIN <= TYPE_MINIMUM (ElfW (Half)))
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&& TYPE_MAXIMUM (ElfW (Half)) <= INT_MAX);
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#ifdef UNEXELF_DEBUG
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# define DEBUG_LOG(expr) fprintf (stderr, #expr " 0x%jx\n", (uintmax_t) (expr))
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#endif
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/* Get the address of a particular section or program header entry,
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* accounting for the size of the entries.
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*/
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@ -546,17 +560,25 @@ typedef struct {
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Apr 23, 1996
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*/
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#define OLD_SECTION_H(n) \
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(*(ElfW (Shdr) *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
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#define NEW_SECTION_H(n) \
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(*(ElfW (Shdr) *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
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#define NEW_PROGRAM_H(n) \
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(*(ElfW (Phdr) *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
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static void *
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entry_address (void *section_h, int idx, int num, int entsize)
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{
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char *h = section_h;
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ptrdiff_t n = idx;
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return h + entsize * n;
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}
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#define PATCH_INDEX(n) \
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do { \
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if ((int) (n) >= old_bss_index) \
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(n)++; } while (0)
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#define OLD_SECTION_H(n) \
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(*(ElfW (Shdr) *) entry_address (old_section_h, n, old_file_h->e_shnum, \
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old_file_h->e_shentsize))
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#define NEW_SECTION_H(n) \
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(*(ElfW (Shdr) *) entry_address (new_section_h, n, new_file_h->e_shnum, \
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new_file_h->e_shentsize))
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#define NEW_PROGRAM_H(n) \
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(*(ElfW (Phdr) *) entry_address (new_program_h, n, new_file_h->e_phnum, \
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new_file_h->e_phentsize))
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#define PATCH_INDEX(n) ((n) += old_bss_index <= (n))
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typedef unsigned char byte;
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/* Round X up to a multiple of Y. */
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@ -564,7 +586,7 @@ typedef unsigned char byte;
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static ElfW (Addr)
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round_up (ElfW (Addr) x, ElfW (Addr) y)
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{
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int rem = x % y;
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ElfW (Addr) rem = x % y;
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if (rem == 0)
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return x;
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return x - rem + y;
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@ -575,33 +597,28 @@ round_up (ElfW (Addr) x, ElfW (Addr) y)
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about the file we are looking in.
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If we don't find the section NAME, that is a fatal error
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if NOERROR is 0; we return -1 if NOERROR is nonzero. */
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if NOERROR is false; return -1 if NOERROR is true. */
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static int
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find_section (const char *name, const char *section_names, const char *file_name,
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ElfW (Ehdr) *old_file_h, ElfW (Shdr) *old_section_h, int noerror)
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ElfW (Ehdr) *old_file_h, ElfW (Shdr) *old_section_h,
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bool noerror)
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{
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int idx;
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for (idx = 1; idx < old_file_h->e_shnum; idx++)
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{
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#ifdef DEBUG
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fprintf (stderr, "Looking for %s - found %s\n", name,
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section_names + OLD_SECTION_H (idx).sh_name);
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char const *found_name = section_names + OLD_SECTION_H (idx).sh_name;
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#ifdef UNEXELF_DEBUG
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fprintf (stderr, "Looking for %s - found %s\n", name, found_name);
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#endif
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if (!strcmp (section_names + OLD_SECTION_H (idx).sh_name,
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name))
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break;
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}
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if (idx == old_file_h->e_shnum)
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{
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if (noerror)
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return -1;
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else
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fatal ("Can't find %s in %s.\n", name, file_name);
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if (strcmp (name, found_name) == 0)
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return idx;
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}
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return idx;
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if (! noerror)
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fatal ("Can't find %s in %s", name, file_name);
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return -1;
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}
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/* ****************************************************************
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@ -616,11 +633,9 @@ find_section (const char *name, const char *section_names, const char *file_name
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void
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unexec (const char *new_name, const char *old_name)
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{
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int new_file, old_file, new_file_size;
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#if defined (emacs) || !defined (DEBUG)
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int new_file, old_file;
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off_t new_file_size;
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void *new_break;
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#endif
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/* Pointers to the base of the image of the two files. */
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caddr_t old_base, new_base;
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@ -654,7 +669,7 @@ unexec (const char *new_name, const char *old_name)
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int old_mdebug_index;
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#endif
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struct stat stat_buf;
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int old_file_size;
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off_t old_file_size;
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/* Open the old file, allocate a buffer of the right size, and read
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in the file contents. */
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@ -662,15 +677,15 @@ unexec (const char *new_name, const char *old_name)
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old_file = open (old_name, O_RDONLY);
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if (old_file < 0)
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fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
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fatal ("Can't open %s for reading: %s", old_name, strerror (errno));
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if (fstat (old_file, &stat_buf) == -1)
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fatal ("Can't fstat (%s): errno %d\n", old_name, errno);
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if (fstat (old_file, &stat_buf) != 0)
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fatal ("Can't fstat (%s): %s", old_name, strerror (errno));
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#if MAP_ANON == 0
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mmap_fd = open ("/dev/zero", O_RDONLY);
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if (mmap_fd < 0)
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fatal ("Can't open /dev/zero for reading: errno %d\n", errno, 0);
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fatal ("Can't open /dev/zero for reading: %s", strerror (errno));
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#endif
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/* We cannot use malloc here because that may use sbrk. If it does,
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@ -678,13 +693,15 @@ unexec (const char *new_name, const char *old_name)
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extra careful to use the correct value of sbrk(0) after
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allocating all buffers in the code below, which we aren't. */
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old_file_size = stat_buf.st_size;
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if (! (0 <= old_file_size && old_file_size <= SIZE_MAX))
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fatal ("File size out of range");
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old_base = mmap (NULL, old_file_size, PROT_READ | PROT_WRITE,
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MAP_ANON | MAP_PRIVATE, mmap_fd, 0);
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if (old_base == MAP_FAILED)
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fatal ("Can't allocate buffer for %s\n", old_name, 0);
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fatal ("Can't allocate buffer for %s: %s", old_name, strerror (errno));
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if (read (old_file, old_base, stat_buf.st_size) != stat_buf.st_size)
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fatal ("Didn't read all of %s: errno %d\n", old_name, errno);
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if (read (old_file, old_base, old_file_size) != old_file_size)
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fatal ("Didn't read all of %s: %s", old_name, strerror (errno));
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/* Get pointers to headers & section names */
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@ -755,12 +772,8 @@ unexec (const char *new_name, const char *old_name)
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old_data_index = find_section (".data", old_section_names,
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old_name, old_file_h, old_section_h, 0);
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#if defined (emacs) || !defined (DEBUG)
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new_break = sbrk (0);
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new_bss_addr = (ElfW (Addr)) new_break;
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#else
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new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
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#endif
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new_data2_addr = old_bss_addr;
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new_data2_size = new_bss_addr - old_bss_addr;
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new_data2_offset = OLD_SECTION_H (old_data_index).sh_offset
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@ -771,38 +784,38 @@ unexec (const char *new_name, const char *old_name)
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section) was unaligned. */
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new_data2_incr = new_data2_size + (new_data2_offset - old_bss_offset);
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#ifdef DEBUG
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#ifdef UNEXELF_DEBUG
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fprintf (stderr, "old_bss_index %d\n", old_bss_index);
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fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
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fprintf (stderr, "old_bss_size %x\n", old_bss_size);
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fprintf (stderr, "old_bss_offset %x\n", old_bss_offset);
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fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
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fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
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fprintf (stderr, "new_data2_size %x\n", new_data2_size);
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fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
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fprintf (stderr, "new_data2_incr %x\n", new_data2_incr);
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DEBUG_LOG (old_bss_addr);
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DEBUG_LOG (old_bss_size);
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DEBUG_LOG (old_bss_offset);
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DEBUG_LOG (new_bss_addr);
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DEBUG_LOG (new_data2_addr);
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DEBUG_LOG (new_data2_size);
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DEBUG_LOG (new_data2_offset);
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DEBUG_LOG (new_data2_incr);
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#endif
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if ((uintptr_t) new_bss_addr < (uintptr_t) old_bss_addr + old_bss_size)
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fatal (".bss shrank when undumping???\n", 0, 0);
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if (new_bss_addr < old_bss_addr + old_bss_size)
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fatal (".bss shrank when undumping");
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/* Set the output file to the right size. Allocate a buffer to hold
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the image of the new file. Set pointers to various interesting
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objects. stat_buf still has old_file data. */
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objects. */
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new_file = open (new_name, O_RDWR | O_CREAT, 0666);
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if (new_file < 0)
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fatal ("Can't creat (%s): errno %d\n", new_name, errno);
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fatal ("Can't creat (%s): %s", new_name, strerror (errno));
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new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_incr;
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new_file_size = old_file_size + old_file_h->e_shentsize + new_data2_incr;
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if (ftruncate (new_file, new_file_size))
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fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
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fatal ("Can't ftruncate (%s): %s", new_name, strerror (errno));
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new_base = mmap (NULL, new_file_size, PROT_READ | PROT_WRITE,
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MAP_ANON | MAP_PRIVATE, mmap_fd, 0);
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if (new_base == MAP_FAILED)
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fatal ("Can't allocate buffer for %s\n", old_name, 0);
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fatal ("Can't allocate buffer for %s: %s", old_name, strerror (errno));
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new_file_h = (ElfW (Ehdr) *) new_base;
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new_program_h = (ElfW (Phdr) *) ((byte *) new_base + old_file_h->e_phoff);
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@ -825,10 +838,10 @@ unexec (const char *new_name, const char *old_name)
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new_file_h->e_shoff += new_data2_incr;
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new_file_h->e_shnum += 1;
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#ifdef DEBUG
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fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
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#ifdef UNEXELF_DEBUG
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DEBUG_LOG (old_file_h->e_shoff);
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fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
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fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
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DEBUG_LOG (new_file_h->e_shoff);
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fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
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#endif
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@ -839,7 +852,7 @@ unexec (const char *new_name, const char *old_name)
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to adjust the offset and address of any segment that is above
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data2, just in case we decide to allow this later. */
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for (n = new_file_h->e_phnum - 1; n >= 0; n--)
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for (n = new_file_h->e_phnum; --n >= 0; )
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{
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/* Compute maximum of all requirements for alignment of section. */
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ElfW (Word) alignment = (NEW_PROGRAM_H (n)).p_align;
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@ -857,7 +870,7 @@ unexec (const char *new_name, const char *old_name)
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> (old_sbss_index == -1
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? old_bss_addr
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: round_up (old_bss_addr, alignment)))
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fatal ("Program segment above .bss in %s\n", old_name, 0);
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fatal ("Program segment above .bss in %s", old_name);
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if (NEW_PROGRAM_H (n).p_type == PT_LOAD
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&& (round_up ((NEW_PROGRAM_H (n)).p_vaddr
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@ -867,7 +880,7 @@ unexec (const char *new_name, const char *old_name)
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break;
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}
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if (n < 0)
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fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
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fatal ("Couldn't find segment next to .bss in %s", old_name);
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/* Make sure that the size includes any padding before the old .bss
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section. */
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@ -875,7 +888,7 @@ unexec (const char *new_name, const char *old_name)
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NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
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#if 0 /* Maybe allow section after data2 - does this ever happen? */
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for (n = new_file_h->e_phnum - 1; n >= 0; n--)
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for (n = new_file_h->e_phnum; --n >= 0; )
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{
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||||
if (NEW_PROGRAM_H (n).p_vaddr
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&& NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
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||||
|
|
@ -894,7 +907,7 @@ unexec (const char *new_name, const char *old_name)
|
|||
|
||||
/* Walk through all section headers, insert the new data2 section right
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before the new bss section. */
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||||
for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++)
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||||
for (n = 1, nn = 1; n < old_file_h->e_shnum; n++, nn++)
|
||||
{
|
||||
caddr_t src;
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||||
/* If it is (s)bss section, insert the new data2 section before it. */
|
||||
|
|
@ -1173,7 +1186,7 @@ unexec (const char *new_name, const char *old_name)
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|||
}
|
||||
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||||
/* Update the symbol values of _edata and _end. */
|
||||
for (n = new_file_h->e_shnum - 1; n; n--)
|
||||
for (n = new_file_h->e_shnum; 0 < --n; )
|
||||
{
|
||||
byte *symnames;
|
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ElfW (Sym) *symp, *symendp;
|
||||
|
|
@ -1233,7 +1246,7 @@ unexec (const char *new_name, const char *old_name)
|
|||
|
||||
/* This loop seeks out relocation sections for the data section, so
|
||||
that it can undo relocations performed by the runtime linker. */
|
||||
for (n = new_file_h->e_shnum - 1; n; n--)
|
||||
for (n = new_file_h->e_shnum; 0 < --n; )
|
||||
{
|
||||
ElfW (Shdr) section = NEW_SECTION_H (n);
|
||||
|
||||
|
|
@ -1293,8 +1306,8 @@ unexec (const char *new_name, const char *old_name)
|
|||
/* Write out new_file, and free the buffers. */
|
||||
|
||||
if (write (new_file, new_base, new_file_size) != new_file_size)
|
||||
fatal ("Didn't write %d bytes to %s: errno %d\n",
|
||||
new_file_size, new_name, errno);
|
||||
fatal ("Didn't write %lu bytes to %s: %s",
|
||||
(unsigned long) new_file_size, new_name, strerror (errno));
|
||||
munmap (old_base, old_file_size);
|
||||
munmap (new_base, new_file_size);
|
||||
|
||||
|
|
@ -1304,18 +1317,18 @@ unexec (const char *new_name, const char *old_name)
|
|||
close (mmap_fd);
|
||||
#endif
|
||||
|
||||
if (close (old_file))
|
||||
fatal ("Can't close (%s): errno %d\n", old_name, errno);
|
||||
if (close (old_file) != 0)
|
||||
fatal ("Can't close (%s): %s", old_name, strerror (errno));
|
||||
|
||||
if (close (new_file))
|
||||
fatal ("Can't close (%s): errno %d\n", new_name, errno);
|
||||
if (close (new_file) != 0)
|
||||
fatal ("Can't close (%s): %s", new_name, strerror (errno));
|
||||
|
||||
if (stat (new_name, &stat_buf) == -1)
|
||||
fatal ("Can't stat (%s): errno %d\n", new_name, errno);
|
||||
if (stat (new_name, &stat_buf) != 0)
|
||||
fatal ("Can't stat (%s): %s", new_name, strerror (errno));
|
||||
|
||||
n = umask (777);
|
||||
umask (n);
|
||||
stat_buf.st_mode |= 0111 & ~n;
|
||||
if (chmod (new_name, stat_buf.st_mode) == -1)
|
||||
fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
|
||||
if (chmod (new_name, stat_buf.st_mode) != 0)
|
||||
fatal ("Can't chmod (%s): %s", new_name, strerror (errno));
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Reference in a new issue