[PATCH 2/3] parse_pack_header_option(): avoid unaligned memory writes
- From
Jeff King <peff@peff.net>
- Date
- Jan 17, 2025, 12:55 UTC
- Message-ID
- <20250117125530.GB2893666@coredump.intra.peff.net>
- In-Reply-To
- <20250117125207.GB2356599@coredump.intra.peff.net>
In order to recreate a pack header in our in-memory buffer, we cast the buffer to a "struct pack_header" and assign the individual fields. This is reported to cause SIGBUS on sparc64 due to alignment issues.
We can work around this by using put_be32() which will write individual bytes into the buffer.
Reported-by: Koakuma <koachan@protonmail.com> Signed-off-by: Jeff King <peff@peff.net> --- Fingers crossed that this is sufficient, and we don't have more alignment problems.
packfile.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/packfile.c b/packfile.c index 2bf9e57330..2d80d80cb3 100644 --- a/packfile.c +++ b/packfile.c @@ -2318,17 +2318,20 @@ int is_promisor_object(struct repository *r, const struct object_id *oid) int parse_pack_header_option(const char *in, unsigned char *out, unsigned int *len) { - struct pack_header *hdr; + unsigned char *hdr; char *c; - hdr = (struct pack_header *)out; - hdr->hdr_signature = htonl(PACK_SIGNATURE); - hdr->hdr_version = htonl(strtoul(in, &c, 10)); + hdr = out; + put_be32(hdr, PACK_SIGNATURE); + hdr += 4; + put_be32(hdr, strtoul(in, &c, 10)); + hdr += 4; if (*c != ',') return -1; - hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10)); + put_be32(hdr, strtoul(c + 1, &c, 10)); + hdr += 4; if (*c) return -1; - *len = sizeof(*hdr); + *len = hdr - out; return 0; }
-- 2.48.1.438.g7fbf7b046e