61 lines
2.3 KiB
Diff
61 lines
2.3 KiB
Diff
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Make sure to check for symlinks even if the pathname is very long:
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https://github.com/libarchive/libarchive/issues/744
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Patch copied from upstream repository:
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https://github.com/libarchive/libarchive/commit/1fa9c7bf90f0862036a99896b0501c381584451a
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From 1fa9c7bf90f0862036a99896b0501c381584451a Mon Sep 17 00:00:00 2001
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From: Tim Kientzle <kientzle@acm.org>
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Date: Sun, 21 Aug 2016 17:11:45 -0700
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Subject: [PATCH] Issue #744 (part of Issue #743): Enforce sandbox with very
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long pathnames
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Because check_symlinks is handled separately from the deep-directory
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support, very long pathnames cause problems. Previously, the code
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ignored most failures to lstat() a path component. In particular,
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this led to check_symlinks always passing for very long paths, which
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in turn provides a way to evade the symlink checks in the sandboxing
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code.
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We now fail on unrecognized lstat() failures, which plugs this
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hole at the cost of disabling deep directory support when the
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user requests sandboxing.
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TODO: This probably cannot be completely fixed without
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entirely reimplementing the deep directory support to
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integrate the symlink checks. I want to reimplement the
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deep directory hanlding someday anyway; openat() and
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related system calls now provide a much cleaner way to
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handle deep directories than the chdir approach used by this
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code.
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---
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libarchive/archive_write_disk_posix.c | 12 +++++++++++-
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1 file changed, 11 insertions(+), 1 deletion(-)
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diff --git a/libarchive/archive_write_disk_posix.c b/libarchive/archive_write_disk_posix.c
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index 39ee3b6..8f0421e 100644
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--- a/libarchive/archive_write_disk_posix.c
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+++ b/libarchive/archive_write_disk_posix.c
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@@ -2401,8 +2401,18 @@ check_symlinks(struct archive_write_disk *a)
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r = lstat(a->name, &st);
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if (r != 0) {
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/* We've hit a dir that doesn't exist; stop now. */
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- if (errno == ENOENT)
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+ if (errno == ENOENT) {
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break;
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+ } else {
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+ /* Note: This effectively disables deep directory
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+ * support when security checks are enabled.
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+ * Otherwise, very long pathnames that trigger
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+ * an error here could evade the sandbox.
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+ * TODO: We could do better, but it would probably
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+ * require merging the symlink checks with the
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+ * deep-directory editing. */
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+ return (ARCHIVE_FAILED);
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+ }
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} else if (S_ISLNK(st.st_mode)) {
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if (c == '\0') {
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/*
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