@matheusbsbs / matheus-bagliano / commits / 93cff9a978

sha1_loose_object_info: return error for corrupted objects

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 <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Jeff King committed Apr 1, 2017 at 04:05 UTC 93cff9a978e1c177ac3e889867004a56773301b2

2 files changed +8 -1

sha1_file.c

+1 -1

@@ -2867,7 +2867,7 @@ static int sha1_loose_object_info(const unsigned char *sha1,

2867 if (status && oi->typep)

2868 *oi->typep = status;

2869 strbuf_release(&hdrbuf);

2870 - return 0;

2870 + return (status < 0) ? status : 0;

2871 }

2872

2873 int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)

t/t1060-object-corruption.sh

@@ -53,6 +53,13 @@ test_expect_success 'streaming a corrupt blob fails' '

53 )

54 '

56 +test_expect_success 'getting type of a corrupt blob fails' '

57 + (

58 + cd bit-error &&

59 + test_must_fail git cat-file -s HEAD:content.t

60 + )

61 +'

62 +

63 test_expect_success 'read-tree -u detects bit-errors in blobs' '

64 (

65 cd bit-error &&