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bspatch: add integer overflow checks

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Introduce a new add_off_t static function that exits with an error
message if there's an overflow, otherwise returns their sum.  Use this
when adding values obtained from the input patch.

Reviewed by:	delphij, allanjude (earlier)
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D7897
This commit is contained in:
emaste 2019-09-26 13:27:25 +00:00
parent 64ad58b605
commit d0260bc283
1 changed files with 26 additions and 9 deletions
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35
usr.bin/bsdiff/bspatch/bspatch.c
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@ -61,6 +61,23 @@ exit_cleanup(void)
warn("unlinkat");
}
static inline off_t
add_off_t(off_t a, off_t b)
{
off_t result;
#if __GNUC__ >= 5 || \
(defined(__has_builtin) && __has_builtin(__builtin_add_overflow))
if (__builtin_add_overflow(a, b, &result))
errx(1, "Corrupt patch");
#else
if ((b > 0 && a > OFF_MAX - b) || (b < 0 && a < OFF_MIN - b))
errx(1, "Corrupt patch");
result = a + b;
#endif
return result;
}
static off_t offtin(u_char *buf)
{
off_t y;
@ -199,12 +216,12 @@ int main(int argc, char *argv[])
err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
if ((cpfbz2 = BZ2_bzReadOpen(&cbz2err, cpf, 0, 0, NULL, 0)) == NULL)
errx(1, "BZ2_bzReadOpen, bz2err = %d", cbz2err);
offset += bzctrllen;
offset = add_off_t(offset, bzctrllen);
if (fseeko(dpf, offset, SEEK_SET))
err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
if ((dpfbz2 = BZ2_bzReadOpen(&dbz2err, dpf, 0, 0, NULL, 0)) == NULL)
errx(1, "BZ2_bzReadOpen, bz2err = %d", dbz2err);
offset += bzdatalen;
offset = add_off_t(offset, bzdatalen);
if (fseeko(epf, offset, SEEK_SET))
err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
if ((epfbz2 = BZ2_bzReadOpen(&ebz2err, epf, 0, 0, NULL, 0)) == NULL)
@ -238,7 +255,7 @@ int main(int argc, char *argv[])
errx(1, "Corrupt patch");
/* Sanity-check */
if (newpos + ctrl[0] > newsize)
if (add_off_t(newpos, ctrl[0]) > newsize)
errx(1, "Corrupt patch");
/* Read diff string */
@ -249,15 +266,15 @@ int main(int argc, char *argv[])
/* Add old data to diff string */
for (i = 0; i < ctrl[0]; i++)
if ((oldpos + i >= 0) && (oldpos + i < oldsize))
if (add_off_t(oldpos, i) < oldsize)
new[newpos + i] += old[oldpos + i];
/* Adjust pointers */
newpos += ctrl[0];
oldpos += ctrl[0];
newpos = add_off_t(newpos, ctrl[0]);
oldpos = add_off_t(oldpos, ctrl[0]);
/* Sanity-check */
if (newpos + ctrl[1] > newsize)
if (add_off_t(newpos, ctrl[1]) > newsize)
errx(1, "Corrupt patch");
/* Read extra string */
@ -267,8 +284,8 @@ int main(int argc, char *argv[])
errx(1, "Corrupt patch");
/* Adjust pointers */
newpos+=ctrl[1];
oldpos+=ctrl[2];
newpos = add_off_t(newpos, ctrl[1]);
oldpos = add_off_t(oldpos, ctrl[2]);
}
/* Clean up the bzip2 reads */