| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.15 05/98] ksmbd: use vfs_llseek instead of dereferencing NULL | Date | Tue, 5 Jul 2022 13:57:23 +0200 |
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From: Jason A. Donenfeld <Jason@zx2c4.com>
commit 067baa9a37b32b95fdeabccde4b0cb6a2cf95f96 upstream.
By not checking whether llseek is NULL, this might jump to NULL. Also, it doesn't check FMODE_LSEEK. Fix this by using vfs_llseek(), which always does the right thing.
Fixes: f44158485826 ("cifsd: add file operations") Cc: stable@vger.kernel.org Cc: linux-cifs@vger.kernel.org Cc: Ronnie Sahlberg <lsahlber@redhat.com> Cc: Hyunchul Lee <hyc.lee@gmail.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reviewed-by: Namjae Jeon <linkinjeon@kernel.org> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- fs/ksmbd/vfs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/ksmbd/vfs.c +++ b/fs/ksmbd/vfs.c @@ -1051,7 +1051,7 @@ int ksmbd_vfs_fqar_lseek(struct ksmbd_fi *out_count = 0; end = start + length; while (start < end && *out_count < in_count) { - extent_start = f->f_op->llseek(f, start, SEEK_DATA); + extent_start = vfs_llseek(f, start, SEEK_DATA); if (extent_start < 0) { if (extent_start != -ENXIO) ret = (int)extent_start; @@ -1061,7 +1061,7 @@ int ksmbd_vfs_fqar_lseek(struct ksmbd_fi if (extent_start >= end) break; - extent_end = f->f_op->llseek(f, extent_start, SEEK_HOLE); + extent_end = vfs_llseek(f, extent_start, SEEK_HOLE); if (extent_end < 0) { if (extent_end != -ENXIO) ret = (int)extent_end;
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