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| author | Audra Mitchell <audra@redhat.com> | 2024-06-26 09:05:11 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-07-18 13:07:42 +0200 |
| commit | 519547760f16eae7803d2658d9524bc5ba7a20a7 (patch) | |
| tree | 00c2aaaaeb555249fb573a2c928469e5ab66136a | |
| parent | b3e1890bc34d8a0ad8de5ba1eedac1d295ce6acd (diff) | |
| download | linux-519547760f16eae7803d2658d9524bc5ba7a20a7.tar.gz linux-519547760f16eae7803d2658d9524bc5ba7a20a7.tar.bz2 linux-519547760f16eae7803d2658d9524bc5ba7a20a7.zip | |
Fix userfaultfd_api to return EINVAL as expected
commit 1723f04caacb32cadc4e063725d836a0c4450694 upstream.
Currently if we request a feature that is not set in the Kernel config we
fail silently and return all the available features. However, the man
page indicates we should return an EINVAL.
We need to fix this issue since we can end up with a Kernel warning should
a program request the feature UFFD_FEATURE_WP_UNPOPULATED on a kernel with
the config not set with this feature.
[ 200.812896] WARNING: CPU: 91 PID: 13634 at mm/memory.c:1660 zap_pte_range+0x43d/0x660
[ 200.820738] Modules linked in:
[ 200.869387] CPU: 91 PID: 13634 Comm: userfaultfd Kdump: loaded Not tainted 6.9.0-rc5+ #8
[ 200.877477] Hardware name: Dell Inc. PowerEdge R6525/0N7YGH, BIOS 2.7.3 03/30/2022
[ 200.885052] RIP: 0010:zap_pte_range+0x43d/0x660
Link: https://lkml.kernel.org/r/20240626130513.120193-1-audra@redhat.com
Fixes: e06f1e1dd499 ("userfaultfd: wp: enabled write protection in userfaultfd API")
Signed-off-by: Audra Mitchell <audra@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/userfaultfd.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index b56e8e31d967..309d4884d5de 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1935,7 +1935,7 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, goto out; features = uffdio_api.features; ret = -EINVAL; - if (uffdio_api.api != UFFD_API || (features & ~UFFD_API_FEATURES)) + if (uffdio_api.api != UFFD_API) goto err_out; ret = -EPERM; if ((features & UFFD_FEATURE_EVENT_FORK) && !capable(CAP_SYS_PTRACE)) @@ -1949,6 +1949,11 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, #ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP; #endif + + ret = -EINVAL; + if (features & ~uffdio_api.features) + goto err_out; + uffdio_api.ioctls = UFFD_API_IOCTLS; ret = -EFAULT; if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api))) |