From: Jeff King Date: Tue, 18 Nov 2025 09:11:27 GMT Subject: [PATCH v2 0/9] asan bonanza Message-ID: <20251118091127.GA4175601@coredump.intra.peff.net> In-Reply-To: <20251112075522.GA978866@coredump.intra.peff.net> On Wed, Nov 12, 2025 at 02:55:22AM -0500, Jeff King wrote: > This series fixes a handful of issues that ASan finds in our test suite > if we tweak a few options to let it look deeper. Here's a v2 based on feedback: - added the extra assertion in the midx code - meson changes are squashed into patch 3 - The cache-tree integer parsing is more robust around total garbage inputs (with no digits at all). I agree with the reviewers that it would be nice to have a robust, reusable integer parsing function. But I think it's non-trivial to do (and I left more comments in the thread). I'd like to stick here to just fixing the memory issues without making anything worse (which I think this version does). Note that since the new helper takes an out-parameter, we have to match the type more strictly to what the callers have. So it is now parse_int(), and not parse_long(). Range diff is below. [1/9]: compat/mmap: mark unused argument in git_munmap() [2/9]: pack-bitmap: handle name-hash lookups in incremental bitmaps [3/9]: Makefile: turn on NO_MMAP when building with ASan [4/9]: cache-tree: avoid strtol() on non-string buffer [5/9]: fsck: assert newline presence in fsck_ident() [6/9]: fsck: avoid strcspn() in fsck_ident() [7/9]: fsck: remove redundant date timestamp check [8/9]: fsck: avoid parse_timestamp() on buffer that isn't NUL-terminated [9/9]: t: enable ASan's strict_string_checks option Makefile | 1 + cache-tree.c | 50 ++++++++++++++++++++++++++---------- compat/mmap.c | 2 +- fsck.c | 71 ++++++++++++++++++++++++++++++++++++--------------- meson.build | 8 +++++- pack-bitmap.c | 29 ++++++++++++++++++--- t/test-lib.sh | 1 + 7 files changed, 122 insertions(+), 40 deletions(-) 1: e24015d41b = 1: 3ce5bd39b5 compat/mmap: mark unused argument in git_munmap() 2: e217fb0e3b ! 2: 9908283c33 pack-bitmap: handle name-hash lookups in incremental bitmaps @@ pack-bitmap.c: static uint32_t bitmap_num_objects(struct bitmap_index *index) +static uint32_t bitmap_name_hash(struct bitmap_index *index, uint32_t pos) +{ + if (bitmap_is_midx(index)) { -+ while (index && pos < index->midx->num_objects_in_base) ++ while (index && pos < index->midx->num_objects_in_base) { ++ ASSERT(bitmap_is_midx(index)); + index = index->base; ++ } + + if (!index) + BUG("NULL base bitmap for object position: %"PRIu32, pos); 3: 8c85dad3c5 < -: ---------- Makefile: turn on NO_MMAP when building with ASan -: ---------- > 3: fe3421f6ec Makefile: turn on NO_MMAP when building with ASan 4: 38d42984da ! 4: 5e228f2c90 cache-tree: avoid strtol() on non-string buffer @@ Commit message further. You'd mostly get stopped by seeing non-digits in the oid field (and if it is likewise truncated, there will still be 20 or more bytes of the index checksum). So it's possible, though - unlikely, to see read off the end of the mmap'd buffer. Of course a + unlikely, to read off the end of the mmap'd buffer. Of course a malicious index file can fake the oid and the index checksum to all (ASCII) 0's. @@ cache-tree.c: void cache_tree_write(struct strbuf *sb, struct cache_tree *root) trace2_region_leave("cache_tree", "write", the_repository); } -+static long parse_long(const char **ptr, unsigned long *len_p) ++static int parse_int(const char **ptr, unsigned long *len_p, int *out) +{ + const char *s = *ptr; + unsigned long len = *len_p; -+ long ret = 0; ++ int ret = 0; + int sign = 1; + + while (len && *s == '-') { @@ cache-tree.c: void cache_tree_write(struct strbuf *sb, struct cache_tree *root) + s++; + len--; + } ++ ++ if (s == *ptr) ++ return -1; ++ + *ptr = s; + *len_p = len; -+ return sign * ret; ++ *out = sign * ret; ++ return 0; +} + static struct cache_tree *read_one(const char **buffer, unsigned long *size_p) @@ cache-tree.c: static struct cache_tree *read_one(const char **buffer, unsigned l - cp = buf; - it->entry_count = strtol(cp, &ep, 10); - if (cp == ep) -+ it->entry_count = parse_long(&buf, &size); -+ if (!size || *buf != ' ') ++ if (parse_int(&buf, &size, &it->entry_count) < 0) goto free_return; - cp = ep; - subtree_nr = strtol(cp, &ep, 10); - if (cp == ep) -- goto free_return; ++ if (!size || *buf != ' ') + goto free_return; - while (size && *buf && *buf != '\n') { - size--; - buf++; - } - if (!size) + buf++; size--; -+ subtree_nr = parse_long(&buf, &size); ++ if (parse_int(&buf, &size, &subtree_nr) < 0) ++ goto free_return; + if (!size || *buf != '\n') goto free_return; buf++; size--; 5: 73e921a34e = 5: 1d6814233c fsck: assert newline presence in fsck_ident() 6: 95e8961df9 = 6: 8cf8152449 fsck: avoid strcspn() in fsck_ident() 7: 34baa85dae = 7: 563c3006e4 fsck: remove redundant date timestamp check 8: f5ff2dc8ef = 8: 6f88309d76 fsck: avoid parse_timestamp() on buffer that isn't NUL-terminated 9: 1b5c0e7ce7 = 9: ad1a1f6a82 t: enable ASan's strict_string_checks option