From: Jia-Ju Bai baijiaju@buaa.edu.cn
[ Upstream commit 97498cd610c0d030a7bd49a7efad974790661162 ]
In a previous commit 2681631c2973 ("fs/ntfs3: Add null pointer check to attr_load_runs_vcn"), ni can be NULL in attr_load_runs_vcn(), and thus it should be checked before being used.
However, in the call stack of this commit, mft_ni in mi_read() is aliased with ni in attr_load_runs_vcn(), and it is also used in mi_read() at two places:
mi_read() rw_lock = &mft_ni->file.run_lock -> No check attr_load_runs_vcn(mft_ni, ...) ni (namely mft_ni) is checked in the previous commit attr_load_runs_vcn(..., &mft_ni->file.run) -> No check
Thus, to avoid possible null-pointer dereferences, the related checks should be added.
These bugs are reported by a static analysis tool implemented by myself, and they are found by extending a known bug fixed in the previous commit. Thus, they could be theoretical bugs.
Signed-off-by: Jia-Ju Bai baijiaju@buaa.edu.cn Signed-off-by: Konstantin Komarov almaz.alexandrovich@paragon-software.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ntfs3/record.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/ntfs3/record.c b/fs/ntfs3/record.c index 2a281cead2bcc..7060f784c2d72 100644 --- a/fs/ntfs3/record.c +++ b/fs/ntfs3/record.c @@ -124,7 +124,7 @@ int mi_read(struct mft_inode *mi, bool is_mft) struct rw_semaphore *rw_lock = NULL;
if (is_mounted(sbi)) { - if (!is_mft) { + if (!is_mft && mft_ni) { rw_lock = &mft_ni->file.run_lock; down_read(rw_lock); } @@ -148,7 +148,7 @@ int mi_read(struct mft_inode *mi, bool is_mft) ni_lock(mft_ni); down_write(rw_lock); } - err = attr_load_runs_vcn(mft_ni, ATTR_DATA, NULL, 0, &mft_ni->file.run, + err = attr_load_runs_vcn(mft_ni, ATTR_DATA, NULL, 0, run, vbo >> sbi->cluster_bits); if (rw_lock) { up_write(rw_lock);