From: Audra Mitchell audra@redhat.com
mainline inclusion from mainline-v6.10 commit 1723f04caacb32cadc4e063725d836a0c4450694 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAGEN5 CVE: CVE-2024-41027
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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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 Conflicts: fs/userfaultfd.c [Yongqiang: Only fix context] Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- fs/userfaultfd.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index e92baac4c3de..3436c9917f51 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1884,7 +1884,7 @@ 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)) @@ -1894,6 +1894,11 @@ 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)))