6.1-stable review patch. If anyone has any objections, please let me know.
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From: Vitaly Grigoryev Vitaly.Grigoryev@kaspersky.com
[ Upstream commit 736fc7bf5f68f6b74a0925b7e072c571838657d2 ]
The MFT record relative to the file being opened contains its runlist, an array containing information about the file's location on the physical disk. Analysis of all Call Stack paths showed that the values of the runlist array, from which LCNs are calculated, are not validated before run_unpack function.
The run_unpack function decodes the compressed runlist data format from MFT attributes (for example, $DATA), converting them into a runs_tree structure, which describes the mapping of virtual clusters (VCN) to logical clusters (LCN). The NTFS3 subsystem also has a shortcut for deleting files from MFT records - in this case, the RUN_DEALLOCATE command is sent to the run_unpack input, and the function logic provides that all data transferred to the runlist about file or directory is deleted without creating a runs_tree structure.
Substituting the runlist in the $DATA attribute of the MFT record for an arbitrary file can lead either to access to arbitrary data on the disk bypassing access checks to them (since the inode access check occurs above) or to destruction of arbitrary data on the disk.
Add overflow check for addition operation.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 4342306f0f0d ("fs/ntfs3: Add file operations and implementation") Signed-off-by: Vitaly Grigoryev Vitaly.Grigoryev@kaspersky.com Signed-off-by: Konstantin Komarov almaz.alexandrovich@paragon-software.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ntfs3/run.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/fs/ntfs3/run.c b/fs/ntfs3/run.c index 12d8682f33b53..340a4cbe8b5ca 100644 --- a/fs/ntfs3/run.c +++ b/fs/ntfs3/run.c @@ -9,6 +9,7 @@ #include <linux/blkdev.h> #include <linux/fs.h> #include <linux/log2.h> +#include <linux/overflow.h>
#include "debug.h" #include "ntfs.h" @@ -982,12 +983,16 @@ int run_unpack(struct runs_tree *run, struct ntfs_sb_info *sbi, CLST ino,
if (!dlcn) return -EINVAL; - lcn = prev_lcn + dlcn; + + if (check_add_overflow(prev_lcn, dlcn, &lcn)) + return -EINVAL; prev_lcn = lcn; } else return -EINVAL;
- next_vcn = vcn64 + len; + if (check_add_overflow(vcn64, len, &next_vcn)) + return -EINVAL; + /* Check boundary. */ if (next_vcn > evcn + 1) return -EINVAL; @@ -1148,7 +1153,8 @@ int run_get_highest_vcn(CLST vcn, const u8 *run_buf, u64 *highest_vcn) return -EINVAL;
run_buf += size_size + offset_size; - vcn64 += len; + if (check_add_overflow(vcn64, len, &vcn64)) + return -EINVAL;
#ifndef CONFIG_NTFS3_64BIT_CLUSTER if (vcn64 > 0x100000000ull)