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authorJunio C Hamano <gitster@pobox.com>2007-09-06 04:58:40 (GMT)
committerJunio C Hamano <gitster@pobox.com>2007-09-06 04:58:40 (GMT)
commit6b763c424e4ace1678ade5310f3ca3ffbd11af2c (patch)
tree9d2f03dd6ec094653b82ea06e3f3ad7228ca7f42
parent5587cac28be66acf5edc2a4b83b67c8cfffbc5e9 (diff)
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git-apply: do not read past the end of buffer
When the preimage we are patching is shorter than what the patch text expects, we tried to match the buffer contents at the "original" line with the fragment in full, without checking we have enough data to match in the preimage. This caused the size of a later memmove() to wrap around and attempt to scribble almost the entire address space. Not good. The code that follows the part this patch touches tries to match the fragment with line offsets. Curiously, that code does not have the problem --- it guards against reading past the end of the preimage. Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r--builtin-apply.c3
-rwxr-xr-xt/t4123-apply-shrink.sh58
2 files changed, 60 insertions, 1 deletions
diff --git a/builtin-apply.c b/builtin-apply.c
index 25b1447..976ec77 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -1514,7 +1514,8 @@ static int find_offset(const char *buf, unsigned long size, const char *fragment
}
/* Exact line number? */
- if (!memcmp(buf + start, fragment, fragsize))
+ if ((start + fragsize <= size) &&
+ !memcmp(buf + start, fragment, fragsize))
return start;
/*
diff --git a/t/t4123-apply-shrink.sh b/t/t4123-apply-shrink.sh
new file mode 100755
index 0000000..984157f
--- /dev/null
+++ b/t/t4123-apply-shrink.sh
@@ -0,0 +1,58 @@
+#!/bin/sh
+
+test_description='apply a patch that is larger than the preimage'
+
+. ./test-lib.sh
+
+cat >F <<\EOF
+1
+2
+3
+4
+5
+6
+7
+8
+999999
+A
+B
+C
+D
+E
+F
+G
+H
+I
+J
+
+EOF
+
+test_expect_success setup '
+
+ git add F &&
+ mv F G &&
+ sed -e "s/1/11/" -e "s/999999/9/" -e "s/H/HH/" <G >F &&
+ git diff >patch &&
+ sed -e "/^\$/d" <G >F &&
+ git add F
+
+'
+
+test_expect_success 'apply should fail gracefully' '
+
+ if git apply --index patch
+ then
+ echo Oops, should not have succeeded
+ false
+ else
+ status=$?
+ echo "Status was $status"
+ if test -f .git/index.lock
+ then
+ echo Oops, should not have crashed
+ false
+ fi
+ fi
+'
+
+test_done