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| 1 | +From 8f600f2df293d539e9e9137f6f82faa1633b97c1 Mon Sep 17 00:00:00 2001 |
| 2 | +From: Paul Eggert < [email protected]> |
| 3 | +Date: Sat, 17 Dec 2022 20:56:29 -0800 |
| 4 | +Subject: [PATCH] sed: fix symlink bufsize readlink check |
| 5 | + |
| 6 | +Problem reported by Hauke Mehrtens. |
| 7 | +* sed/utils.c (follow_symlink): Fix typo when checking size of |
| 8 | +second and later symlink, when that symlink is so large that it |
| 9 | +does not fit into the buffer. Although the bug is not a buffer |
| 10 | +overflow, it does cause sed to mishandle the symlink. |
| 11 | +* testsuite/follow-symlinks.sh: Test for the bug. |
| 12 | +--- |
| 13 | + sed/utils.c | 2 +- |
| 14 | + testsuite/follow-symlinks.sh | 13 +++++++++++++ |
| 15 | + 3 files changed, 18 insertions(+), 1 deletion(-) |
| 16 | + |
| 17 | +--- a/sed/utils.c |
| 18 | ++++ b/sed/utils.c |
| 19 | +@@ -345,7 +345,7 @@ follow_symlink (const char *fname) |
| 20 | + while ((linklen = (buf_used < buf_size |
| 21 | + ? readlink (fn, buf + buf_used, buf_size - buf_used) |
| 22 | + : 0)) |
| 23 | +- == buf_size) |
| 24 | ++ == buf_size - buf_used) |
| 25 | + { |
| 26 | + buf = xpalloc (buf, &buf_size, 1, SSIZE_IDX_MAX, 1); |
| 27 | + if (num_links) |
| 28 | +--- a/testsuite/follow-symlinks.sh |
| 29 | ++++ b/testsuite/follow-symlinks.sh |
| 30 | +@@ -73,4 +73,17 @@ compare_ exp-la-abs out-la-abs || fail=1 |
| 31 | + ln -s la-loop la-loop || framework_failure_ |
| 32 | + sed --follow-symlinks -i s/a/b/ la-loop && fail=1 |
| 33 | + |
| 34 | ++# symlink of length 128 |
| 35 | ++long=d/ |
| 36 | ++for i in 2 3 4 5 6 7; do |
| 37 | ++ long=$long$long |
| 38 | ++done |
| 39 | ++dir=${long%/d/} |
| 40 | ++file=$dir/xx |
| 41 | ++mkdir -p $dir && |
| 42 | ++echo x >$file && |
| 43 | ++ln -s $file yy && |
| 44 | ++ln -s yy xx || framework_failure_ |
| 45 | ++sed -i --follow-symlinks s/x/y/ xx || fail=1 |
| 46 | ++ |
| 47 | + Exit $fail |
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