[PATCH 4/7] pkt-line: prepare buffer before handling ERR packets
- From
Jeff King <peff@peff.net>
- Date
- Apr 13, 2019, 05:54 UTC
- Message-ID
- <20190413055401.GD19495@sigill.intra.peff.net>
- In-Reply-To
- <20190413055127.GA32340@sigill.intra.peff.net>
Since 2d103c31c2 (pack-protocol.txt: accept error packets in any context, 2018-12-29), the pktline code will detect an ERR packet and die automatically, saving the caller from dealing with it. But we do so too early in the function, before we have terminated the buffer with a NUL.
As a result, passing the ERR message to die() may result in us printing random cruft from a previous packet. This doesn't trigger memory tools like ASan because we reuse the same buffer over and over (so the contents are valid and initialized; they're just stale).
We can see demonstrate this by tightening the regex we use to match the error message in t5516; without this patch, git-fetch will accidentally print the capabilities from the (much longer) initial packet we received.
By moving the ERR code later in the function we get a few other benefits, too:
- we'll now chomp any newline sent by the other side (which is what we
want, since die() will add its own newline)- we'll now mention the ERR packet with GIT_TRACE_PACKET
Signed-off-by: Jeff King <peff@peff.net> --- pkt-line.c | 9 +++++---- t/t5516-fetch-push.sh | 2 +- 2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/pkt-line.c b/pkt-line.c index ffd7220544..c9ed780d0b 100644 --- a/pkt-line.c +++ b/pkt-line.c @@ -350,16 +350,17 @@ enum packet_read_status packet_read_with_status(int fd, char **src_buffer, return PACKET_READ_EOF; } - if ((options & PACKET_READ_DIE_ON_ERR_PACKET) && - starts_with(buffer, "ERR ")) - die(_("remote error: %s"), buffer + 4); - if ((options & PACKET_READ_CHOMP_NEWLINE) && len && buffer[len-1] == '\n') len--; buffer[len] = 0; packet_trace(buffer, len, 0); + + if ((options & PACKET_READ_DIE_ON_ERR_PACKET) && + starts_with(buffer, "ERR ")) + die(_("remote error: %s"), buffer + 4); + *pktlen = len; return PACKET_READ_NORMAL; } diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh index 747dc4c31d..98ef71b48c 100755 --- a/t/t5516-fetch-push.sh +++ b/t/t5516-fetch-push.sh @@ -1241,7 +1241,7 @@ do git fetch ../testrepo/.git $SHA1_2 && git cat-file commit $SHA1_2 && test_must_fail git fetch ../testrepo/.git $SHA1_3 2>err && - test_i18ngrep "remote error:.*not our ref" err + test_i18ngrep "remote error:.*not our ref.*$SHA1_3\$" err ) ' done
-- 2.21.0.931.gd0bc72a411