diff options
| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2025-11-17 17:43:42 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2025-11-18 15:27:34 +0100 |
| commit | 803abedbd540617f136a2c4d7066ff2e304f016d (patch) | |
| tree | 8161c9a3f4d7f29af41ba72b9875fb005bc1d774 /lib/iov_iter.c | |
| parent | 4db1df7a7217827ee7f8a3414932e250f1ac2204 (diff) | |
iov_iter: Add missing speculation barrier to copy_from_user_iter()
The results of "access_ok()" can be mis-speculated. The result is that
the CPU can end speculatively:
if (access_ok(from, size))
// Right here
For the same reason as done in copy_from_user() in commit 74e19ef0ff80
("uaccess: Add speculation barrier to copy_from_user()"), add a speculation
barrier to copy_from_user_iter().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/6b73e69cc7168c89df4eab0a216e3ed4cca36b0a.1763396724.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'lib/iov_iter.c')
| -rw-r--r-- | lib/iov_iter.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c index a589935bf302..896760bad455 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -49,11 +49,19 @@ size_t copy_from_user_iter(void __user *iter_from, size_t progress, if (should_fail_usercopy()) return len; - if (can_do_masked_user_access()) + if (can_do_masked_user_access()) { iter_from = mask_user_address(iter_from); - else if (!access_ok(iter_from, len)) - return res; + } else { + if (!access_ok(iter_from, len)) + return res; + /* + * Ensure that bad access_ok() speculation will not + * lead to nasty side effects *after* the copy is + * finished: + */ + barrier_nospec(); + } to += progress; instrument_copy_from_user_before(to, iter_from, len); res = raw_copy_from_user(to, iter_from, len); |