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a941d39460
In GNU patch through 2.7.6, the following of symlinks is mishandled in
certain cases other than input files. This affects inp.c and util.c.
https://nvd.nist.gov/vuln/detail/CVE-2019-13636
Signed-off-by: Russell Senior <russell@personaltelco.net>
(cherry picked from commit 995bcc5329)
109 lines
3.7 KiB
Diff
109 lines
3.7 KiB
Diff
From dce4683cbbe107a95f1f0d45fabc304acfb5d71a Mon Sep 17 00:00:00 2001
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From: Andreas Gruenbacher <agruen@gnu.org>
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Date: Mon, 15 Jul 2019 16:21:48 +0200
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Subject: Don't follow symlinks unless --follow-symlinks is given
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* src/inp.c (plan_a, plan_b), src/util.c (copy_to_fd, copy_file,
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append_to_file): Unless the --follow-symlinks option is given, open files with
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the O_NOFOLLOW flag to avoid following symlinks. So far, we were only doing
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that consistently for input files.
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* src/util.c (create_backup): When creating empty backup files, (re)create them
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with O_CREAT | O_EXCL to avoid following symlinks in that case as well.
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---
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src/inp.c | 12 ++++++++++--
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src/util.c | 14 +++++++++++---
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2 files changed, 21 insertions(+), 5 deletions(-)
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diff --git a/src/inp.c b/src/inp.c
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index 32d0919..22d7473 100644
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--- a/src/inp.c
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+++ b/src/inp.c
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@@ -238,8 +238,13 @@ plan_a (char const *filename)
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{
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if (S_ISREG (instat.st_mode))
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{
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- int ifd = safe_open (filename, O_RDONLY|binary_transput, 0);
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+ int flags = O_RDONLY | binary_transput;
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size_t buffered = 0, n;
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+ int ifd;
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+
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+ if (! follow_symlinks)
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+ flags |= O_NOFOLLOW;
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+ ifd = safe_open (filename, flags, 0);
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if (ifd < 0)
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pfatal ("can't open file %s", quotearg (filename));
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@@ -340,6 +345,7 @@ plan_a (char const *filename)
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static void
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plan_b (char const *filename)
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{
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+ int flags = O_RDONLY | binary_transput;
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int ifd;
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FILE *ifp;
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int c;
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@@ -353,7 +359,9 @@ plan_b (char const *filename)
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if (instat.st_size == 0)
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filename = NULL_DEVICE;
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- if ((ifd = safe_open (filename, O_RDONLY | binary_transput, 0)) < 0
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+ if (! follow_symlinks)
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+ flags |= O_NOFOLLOW;
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+ if ((ifd = safe_open (filename, flags, 0)) < 0
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|| ! (ifp = fdopen (ifd, binary_transput ? "rb" : "r")))
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pfatal ("Can't open file %s", quotearg (filename));
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if (TMPINNAME_needs_removal)
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diff --git a/src/util.c b/src/util.c
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index 1cc08ba..fb38307 100644
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--- a/src/util.c
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+++ b/src/util.c
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@@ -388,7 +388,7 @@ create_backup (char const *to, const struct stat *to_st, bool leave_original)
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try_makedirs_errno = ENOENT;
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safe_unlink (bakname);
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- while ((fd = safe_open (bakname, O_CREAT | O_WRONLY | O_TRUNC, 0666)) < 0)
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+ while ((fd = safe_open (bakname, O_CREAT | O_EXCL | O_WRONLY | O_TRUNC, 0666)) < 0)
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{
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if (errno != try_makedirs_errno)
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pfatal ("Can't create file %s", quotearg (bakname));
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@@ -579,10 +579,13 @@ create_file (char const *file, int open_flags, mode_t mode,
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static void
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copy_to_fd (const char *from, int tofd)
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{
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+ int from_flags = O_RDONLY | O_BINARY;
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int fromfd;
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ssize_t i;
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- if ((fromfd = safe_open (from, O_RDONLY | O_BINARY, 0)) < 0)
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+ if (! follow_symlinks)
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+ from_flags |= O_NOFOLLOW;
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+ if ((fromfd = safe_open (from, from_flags, 0)) < 0)
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pfatal ("Can't reopen file %s", quotearg (from));
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while ((i = read (fromfd, buf, bufsize)) != 0)
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{
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@@ -625,6 +628,8 @@ copy_file (char const *from, char const *to, struct stat *tost,
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else
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{
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assert (S_ISREG (mode));
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+ if (! follow_symlinks)
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+ to_flags |= O_NOFOLLOW;
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tofd = create_file (to, O_WRONLY | O_BINARY | to_flags, mode,
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to_dir_known_to_exist);
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copy_to_fd (from, tofd);
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@@ -640,9 +645,12 @@ copy_file (char const *from, char const *to, struct stat *tost,
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void
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append_to_file (char const *from, char const *to)
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{
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+ int to_flags = O_WRONLY | O_APPEND | O_BINARY;
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int tofd;
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- if ((tofd = safe_open (to, O_WRONLY | O_BINARY | O_APPEND, 0)) < 0)
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+ if (! follow_symlinks)
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+ to_flags |= O_NOFOLLOW;
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+ if ((tofd = safe_open (to, to_flags, 0)) < 0)
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pfatal ("Can't reopen file %s", quotearg (to));
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copy_to_fd (from, tofd);
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if (close (tofd) != 0)
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--
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cgit v1.0-41-gc330
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