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authorAudra Mitchell <[email protected]>2024-06-26 09:05:11 -0400
committerAndrew Morton <[email protected]>2024-07-03 22:40:36 -0700
commit1723f04caacb32cadc4e063725d836a0c4450694 (patch)
tree6b26b980a3a030c622ef14816960fc9568086bd2
parenta34acf30b19bc4ee3ba2f1082756ea2604c19138 (diff)
Fix userfaultfd_api to return EINVAL as expected
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/[email protected] Fixes: e06f1e1dd499 ("userfaultfd: wp: enabled write protection in userfaultfd API") Signed-off-by: Audra Mitchell <[email protected]> Cc: Al Viro <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Christian Brauner <[email protected]> Cc: Jan Kara <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Peter Xu <[email protected]> Cc: Rafael Aquini <[email protected]> Cc: Shaohua Li <[email protected]> Cc: Shuah Khan <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]>
-rw-r--r--fs/userfaultfd.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index eee7320ab0b0..17e409ceaa33 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -2057,7 +2057,7 @@ 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))
@@ -2081,6 +2081,11 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx,
uffdio_api.features &= ~UFFD_FEATURE_WP_UNPOPULATED;
uffdio_api.features &= ~UFFD_FEATURE_WP_ASYNC;
#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)))