From: Bart Van Assche bvanassche@acm.org
[ Upstream commit ec16b147a55bfa14e858234eb7b1a7c8e7cd5021 ]
Reject values that are valid rw_hints after truncation but not before truncation by passing an untruncated value to rw_hint_valid().
Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: Kanchan Joshi joshi.k@samsung.com Cc: Jeff Layton jlayton@kernel.org Cc: Chuck Lever chuck.lever@oracle.com Cc: Jens Axboe axboe@kernel.dk Cc: Stephen Rothwell sfr@canb.auug.org.au Fixes: 5657cb0797c4 ("fs/fcntl: use copy_to/from_user() for u64 types") Signed-off-by: Bart Van Assche bvanassche@acm.org Link: https://lore.kernel.org/r/20240202203926.2478590-2-bvanassche@acm.org Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/fcntl.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/fs/fcntl.c b/fs/fcntl.c index e871009f6c889..9f606714d081b 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -268,7 +268,7 @@ static int f_getowner_uids(struct file *filp, unsigned long arg) } #endif
-static bool rw_hint_valid(enum rw_hint hint) +static bool rw_hint_valid(u64 hint) { switch (hint) { case RWH_WRITE_LIFE_NOT_SET: @@ -288,19 +288,17 @@ static long fcntl_rw_hint(struct file *file, unsigned int cmd, { struct inode *inode = file_inode(file); u64 __user *argp = (u64 __user *)arg; - enum rw_hint hint; - u64 h; + u64 hint;
switch (cmd) { case F_GET_RW_HINT: - h = inode->i_write_hint; - if (copy_to_user(argp, &h, sizeof(*argp))) + hint = inode->i_write_hint; + if (copy_to_user(argp, &hint, sizeof(*argp))) return -EFAULT; return 0; case F_SET_RW_HINT: - if (copy_from_user(&h, argp, sizeof(h))) + if (copy_from_user(&hint, argp, sizeof(hint))) return -EFAULT; - hint = (enum rw_hint) h; if (!rw_hint_valid(hint)) return -EINVAL;