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@xxxxxxxxxxx>
---
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 defce6a5c8e1..dfa1fed9c0d9 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);
--
2.34.1
