40 lines
1.4 KiB
Diff
40 lines
1.4 KiB
Diff
From 92d055879d510a1a51315301ea788445cd11aacb Mon Sep 17 00:00:00 2001
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From: Lukas Czerner <lczerner@redhat.com>
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Date: Fri, 6 Aug 2021 11:58:16 +0200
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Subject: [PATCH 40/46] libext2fs: fix unexpected NULL variable
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Content-Type: text/plain
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The ext2fs_check_mount_point() function can be called with mtpt being
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NULL as for example from ext2fs_check_if_mounted(). However in the
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is_swap_device condition we use the mtpt in strncpy without checking
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whether it is non-null first.
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This should not be a problem on linux since the previous attempt to open
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the device exclusively would have prevented us from ever reaching the
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problematic strncpy. However it's still a bug and can cause problems on
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other systems, fix it by conditioning strncpy on mtpt not being null.
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Signed-off-by: Lukas Czerner <lczerner@redhat.com>
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Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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---
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lib/ext2fs/ismounted.c | 3 ++-
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1 file changed, 2 insertions(+), 1 deletion(-)
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diff --git a/lib/ext2fs/ismounted.c b/lib/ext2fs/ismounted.c
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index 46d330d9..c28475d4 100644
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--- a/lib/ext2fs/ismounted.c
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+++ b/lib/ext2fs/ismounted.c
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@@ -393,7 +393,8 @@ errcode_t ext2fs_check_mount_point(const char *device, int *mount_flags,
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if (is_swap_device(device)) {
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*mount_flags = EXT2_MF_MOUNTED | EXT2_MF_SWAP;
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- strncpy(mtpt, "<swap>", mtlen);
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+ if (mtpt)
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+ strncpy(mtpt, "<swap>", mtlen);
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} else {
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#ifdef HAVE_SETMNTENT
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retval = check_mntent(device, mount_flags, mtpt, mtlen);
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--
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2.35.1
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