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fs: Fix rw_hint validation

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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: 5657cb0797 ("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>
This commit is contained in:
Bart Van Assche 2024-02-02 12:39:20 -08:00 committed by Christian Brauner
parent 6613476e22
commit ec16b147a5
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GPG Key ID: 91C61BC06578DCA2
1 changed files with 5 additions and 7 deletions
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12
fs/fcntl.c
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@ -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;