http-push: fix construction of hex value from path

The get_oid_hex_from_objpath takes care of creating a oid from a pathname. It does this by memcpy'ing the first two bytes of the path to the "hex" string, then skipping the '/', and then copying the rest of the path to the "hex" string. Currently it fails to increase the pointer to the hex string, so the second memcpy invocation just mashes over what was copied in the first one, and leaves the last two bytes in the string uninitialized. This breaks valgrind in t5540, although the test passes without valgrind: ==5490== Use of uninitialised value of size 8 ==5490== at 0x13C6B5: hexval (cache.h:1238) ==5490== by 0x13C6DB: hex2chr (cache.h:1247) ==5490== by 0x13C734: get_sha1_hex (hex.c:42) ==5490== by 0x13C78E: get_oid_hex (hex.c:53) ==5490== by 0x118BDA: get_oid_hex_from_objpath (http-push.c:1023) ==5490== by 0x118C92: process_ls_object (http-push.c:1038) ==5490== by 0x118E5B: handle_remote_ls_ctx (http-push.c:1077) ==5490== by 0x118227: xml_end_tag (http-push.c:815) ==5490== by 0x50C1448: ??? (in /usr/lib/libexpat.so.1.6.6) ==5490== by 0x50C221B: ??? (in /usr/lib/libexpat.so.1.6.6) ==5490== by 0x50BFBF2: ??? (in /usr/lib/libexpat.so.1.6.6) ==5490== by 0x50C0B24: ??? (in /usr/lib/libexpat.so.1.6.6) ==5490== Uninitialised value was created by a stack allocation ==5490== at 0x118B63: get_oid_hex_from_objpath (http-push.c:1012) ==5490== Fix this by correctly incrementing the pointer to the "hex" variable, so the first two bytes are left untouched by the memcpy call, and the last two bytes are correctly initialized. Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Thomas Gummerer committed Oct 3, 2017 at 20:57 UTC 51bfb734df43dc2d9ddbc7234a8723a7b1cfb322
1 file changed +1 -1
http-push.c
+1 -1
@@ -1017,7 +1017,7 @@ static int get_oid_hex_from_objpath(const char *path, struct object_id *oid)
1017 memcpy(hex, path, 2);
1018 path += 2;
1019 path++; /* skip '/' */
1020 - memcpy(hex, path, GIT_SHA1_HEXSZ - 2);
1020 + memcpy(hex + 2, path, GIT_SHA1_HEXSZ - 2);
1021
1022 return get_oid_hex(hex, oid);
1023 }