When sha1_loose_object_info() finds that a loose object file
cannot be stat(2)ed or mmap(2)ed, it returns -1 to signal an
error to the caller. However, if it found that the loose
object file is corrupt and the object data cannot be used
from it, it stuffs OBJ_BAD into "type" field of the
object_info, but returns zero (i.e., success), which can
confuse callers.
This is due to 052fe5eac (sha1_loose_object_info: make type
lookup optional, 2013-07-12), which switched the return to a
strict success/error, rather than returning the type (but
botched the return).
Callers of regular sha1_object_info() don't notice the
difference, as that function returns the type (which is
OBJ_BAD in this case). However, direct callers of
sha1_object_info_extended() see the function return success,
but without setting any meaningful values in the object_info
struct, leading them to access potentially uninitialized
memory.
The easiest way to see the bug is via "cat-file -s", which
will happily ignore the corruption and report whatever
value happened to be in the "size" variable.
Signed-off-by: Jeff King <p...@peff.net>
---
So not only does it not fail, but running with --valgrind complains.
sha1_file.c | 2 +-
t/t1060-object-corruption.sh | 7 +++++++
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/sha1_file.c b/sha1_file.c
index 71063890f..368c89b5c 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -2952,7 +2952,7 @@ static int sha1_loose_object_info(const unsigned char
*sha1,
if (status && oi->typep)
*oi->typep = status;
strbuf_release(&hdrbuf);
- return 0;
+ return (status < 0) ? status : 0;
}
int sha1_object_info_extended(const unsigned char *sha1, struct object_info
*oi, unsigned flags)
diff --git a/t/t1060-object-corruption.sh b/t/t1060-object-corruption.sh
index 3f8705139..3a88d79c5 100755
--- a/t/t1060-object-corruption.sh
+++ b/t/t1060-object-corruption.sh
@@ -53,6 +53,13 @@ test_expect_success 'streaming a corrupt blob fails' '
)
'
+test_expect_success 'getting type of a corrupt blob fails' '
+ (
+ cd bit-error &&
+ test_must_fail git cat-file -s HEAD:content.t
+ )
+'
+
test_expect_success 'read-tree -u detects bit-errors in blobs' '
(
cd bit-error &&
--
2.12.2.943.g91cb50fd8
