A corrupt Subversion-format delta can request reads past the end of
the preimage. Set sliding_view::max_off so such corruption is caught
when it appears rather than blocking in an impossible-to-fulfill
read() when input is coming from a socket or pipe.
Inspired-by: Ramkumar Ramachandra <artagnon@xxxxxxxxx>
Signed-off-by: Jonathan Nieder <jrnieder@xxxxxxxxx>
---
The title feature. Thanks for reading.
t/t9010-svn-fe.sh | 40 +++++++++++++++++++++++++++++++++++++---
vcs-svn/fast_export.c | 15 +++++++++------
2 files changed, 46 insertions(+), 9 deletions(-)
diff --git a/t/t9010-svn-fe.sh b/t/t9010-svn-fe.sh
index f24f004..b7eed24 100755
--- a/t/t9010-svn-fe.sh
+++ b/t/t9010-svn-fe.sh
@@ -18,12 +18,13 @@ reinit_git () {
try_dump () {
input=$1 &&
- maybe_fail=${2:+test_$2} &&
+ maybe_fail_svnfe=${2:+test_$2} &&
+ maybe_fail_fi=${3:+test_$3} &&
{
- $maybe_fail test-svn-fe "$input" >stream 3<backflow &
+ $maybe_fail_svnfe test-svn-fe "$input" >stream 3<backflow &
} &&
- git fast-import --cat-blob-fd=3 <stream 3>backflow &&
+ $maybe_fail_fi git fast-import --cat-blob-fd=3 <stream 3>backflow &&
wait $!
}
@@ -1047,6 +1048,39 @@ test_expect_success PIPE 'deltas need not consume the whole preimage' '
test_cmp expect.3 actual.3
'
+test_expect_success PIPE 'no hang for delta trying to read past end of preimage' '
+ reinit_git &&
+ {
+ # COPY 1
+ printf "SVNQ%b%b" "Q\001\001\002Q" "\001Q" |
+ q_to_nul
+ } >greedy.delta &&
+ {
+ cat <<-\EOF &&
+ SVN-fs-dump-format-version: 3
+
+ Revision-number: 1
+ Prop-content-length: 10
+ Content-length: 10
+
+ PROPS-END
+
+ Node-path: bootstrap
+ Node-kind: file
+ Node-action: add
+ Text-delta: true
+ Prop-content-length: 10
+ EOF
+ echo Text-content-length: $(wc -c <greedy.delta) &&
+ echo Content-length: $((10 + $(wc -c <greedy.delta))) &&
+ echo &&
+ echo PROPS-END &&
+ cat greedy.delta &&
+ echo
+ } >greedydelta.dump &&
+ try_dump greedydelta.dump must_fail might_fail
+'
+
test_expect_success 'set up svn repo' '
svnconf=$PWD/svnconf &&
mkdir -p "$svnconf" &&
diff --git a/vcs-svn/fast_export.c b/vcs-svn/fast_export.c
index 96a75d5..97f5fdf 100644
--- a/vcs-svn/fast_export.c
+++ b/vcs-svn/fast_export.c
@@ -198,8 +198,7 @@ static long apply_delta(off_t len, struct line_buffer *input,
const char *old_data, uint32_t old_mode)
{
long ret;
- off_t preimage_len = 0;
- struct sliding_view preimage = SLIDING_VIEW_INIT(&report_buffer, -1);
+ struct sliding_view preimage = SLIDING_VIEW_INIT(&report_buffer, 0);
FILE *out;
if (init_postimage() || !(out = buffer_tmpfile_rewind(&postimage)))
@@ -211,19 +210,23 @@ static long apply_delta(off_t len, struct line_buffer *input,
printf("cat-blob %s\n", old_data);
fflush(stdout);
response = get_response_line();
- if (parse_cat_response_line(response, &preimage_len))
+ if (parse_cat_response_line(response, &preimage.max_off))
die("invalid cat-blob response: %s", response);
+ check_preimage_overflow(preimage.max_off, 1);
}
if (old_mode == REPO_MODE_LNK) {
strbuf_addstr(&preimage.buf, "link ");
- check_preimage_overflow(preimage_len, strlen("link "));
- preimage_len += strlen("link ");
+ check_preimage_overflow(preimage.max_off, strlen("link "));
+ preimage.max_off += strlen("link ");
+ check_preimage_overflow(preimage.max_off, 1);
}
if (svndiff0_apply(input, len, &preimage, out))
die("cannot apply delta");
if (old_data) {
/* Read the remainder of preimage and trailing newline. */
- if (move_window(&preimage, preimage_len, 1))
+ assert(!signed_add_overflows(preimage.max_off, 1));
+ preimage.max_off++; /* room for newline */
+ if (move_window(&preimage, preimage.max_off - 1, 1))
die("cannot seek to end of input");
if (preimage.buf.buf[0] != '\n')
die("missing newline after cat-blob response");
--
1.7.5.1
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