Re: [PATCH 2/2] Make hash-object more robust against malformed objects

Nguyễn Thái Ngọc Duy wrote:

Commits, trees and tags have structure. Don't let users feed git
with malformed ones. Sooner or later git will die() when
encountering them.

Note that this patch does not check semantics. A tree that points
to non-existent objects is perfectly OK (and should be so, users
may choose to add commit first, then its associated tree for example)

Signed-off-by: Nguyễn Thái Ngọc Duy <redacted>

This patch makes t9350 fail under valgrind:

expecting success: 

        TAG=$(git hash-object -t tag -w tag-content) &&
        git update-ref refs/tags/sonnenschein $TAG &&
        git fast-export -C -C --signed-tags=strip --all > output &&
        test $(grep -c "^tag " output) = 4 &&
        ! grep "Unspecified Tagger" output &&
        git fast-export -C -C --signed-tags=strip --all \
                --fake-missing-tagger > output &&
        test $(grep -c "^tag " output) = 4 &&
        grep "Unspecified Tagger" output


==2862== Invalid read of size 1
==2862==    at 0x4F0C34: prefixcmp (strbuf.c:9)
==2862==    by 0x4F4FB3: parse_tag_buffer (tag.c:109)
==2862==    by 0x4EC686: check_tag (sha1_file.c:2499)
==2862==    by 0x4EC77F: index_mem (sha1_file.c:2529)
==2862==    by 0x4EC934: index_fd (sha1_file.c:2563)
==2862==    by 0x4379C9: hash_fd (hash-object.c:17)
==2862==    by 0x437A86: hash_object (hash-object.c:33)
==2862==    by 0x437E82: cmd_hash_object (hash-object.c:126)
==2862==    by 0x404771: run_builtin (git.c:290)
==2862==    by 0x4048FC: handle_internal_command (git.c:448)
==2862==    by 0x4049E7: run_argv (git.c:492)
==2862==    by 0x404B43: main (git.c:565)
==2862==  Address 0x55abb77 is 0 bytes after a block of size 71 alloc'd
==2862==    at 0x4C20E1C: malloc (vg_replace_malloc.c:195)
==2862==    by 0x504A7C: xmalloc (wrapper.c:35)
==2862==    by 0x4EC8E8: index_fd (sha1_file.c:2561)
==2862==    by 0x4379C9: hash_fd (hash-object.c:17)
==2862==    by 0x437A86: hash_object (hash-object.c:33)
==2862==    by 0x437E82: cmd_hash_object (hash-object.c:126)
==2862==    by 0x404771: run_builtin (git.c:290)
==2862==    by 0x4048FC: handle_internal_command (git.c:448)
==2862==    by 0x4049E7: run_argv (git.c:492)
==2862==    by 0x404B43: main (git.c:565)
==2862== 
==2862== Invalid read of size 1
==2862==    at 0x4F0C50: prefixcmp (strbuf.c:10)
==2862==    by 0x4F4FB3: parse_tag_buffer (tag.c:109)
==2862==    by 0x4EC686: check_tag (sha1_file.c:2499)
==2862==    by 0x4EC77F: index_mem (sha1_file.c:2529)
==2862==    by 0x4EC934: index_fd (sha1_file.c:2563)
==2862==    by 0x4379C9: hash_fd (hash-object.c:17)
==2862==    by 0x437A86: hash_object (hash-object.c:33)
==2862==    by 0x437E82: cmd_hash_object (hash-object.c:126)
==2862==    by 0x404771: run_builtin (git.c:290)
==2862==    by 0x4048FC: handle_internal_command (git.c:448)
==2862==    by 0x4049E7: run_argv (git.c:492)
==2862==    by 0x404B43: main (git.c:565)
==2862==  Address 0x55abb77 is 0 bytes after a block of size 71 alloc'd
==2862==    at 0x4C20E1C: malloc (vg_replace_malloc.c:195)
==2862==    by 0x504A7C: xmalloc (wrapper.c:35)
==2862==    by 0x4EC8E8: index_fd (sha1_file.c:2561)
==2862==    by 0x4379C9: hash_fd (hash-object.c:17)
==2862==    by 0x437A86: hash_object (hash-object.c:33)
==2862==    by 0x437E82: cmd_hash_object (hash-object.c:126)
==2862==    by 0x404771: run_builtin (git.c:290)
==2862==    by 0x4048FC: handle_internal_command (git.c:448)
==2862==    by 0x4049E7: run_argv (git.c:492)
==2862==    by 0x404B43: main (git.c:565)
==2862== 
not ok - 15 cope with tagger-less tags
#       
#       
#               TAG=$(git hash-object -t tag -w tag-content) &&
#               git update-ref refs/tags/sonnenschein $TAG &&
#               git fast-export -C -C --signed-tags=strip --all > output &&
#               test $(grep -c "^tag " output) = 4 &&
#               ! grep "Unspecified Tagger" output &&
#               git fast-export -C -C --signed-tags=strip --all \
#                       --fake-missing-tagger > output &&
#               test $(grep -c "^tag " output) = 4 &&
#               grep "Unspecified Tagger" output
#       
#       

-- 
Thomas Rast
trast@{inf,student}.ethz.ch