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FAILED: patch "[PATCH] ksmbd: prevent out-of-bounds reads in share config responses" failed to apply to 6.6-stable tree

PATCH New [email protected] 2 participants 3 messages Sep 14

Subsystems (2)
Stable branch Kernel SMB3 server (ksmbd)
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[email protected]

author maintainer
#0 lore raw

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x f25e93768fcc5d8287e50b1ec52a42e4c276df34
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026091411-kept-parish-8e82@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From f25e93768fcc5d8287e50b1ec52a42e4c276df34 Mon Sep 17 00:00:00 2001
From: Namjae Jeon <[email protected]>
Date: Fri, 28 Aug 2026 08:39:57 +0900
Subject: [PATCH] ksmbd: prevent out-of-bounds reads in share config responses

Validate IPC share configuration payload sizes before consuming variable-length fields. Bound veto list parsing and account for the separator byte when deriving the path length.

Fixes a677ebd8ca2f ("ksmbd: validate payload size in ipc response")
Reported-by Kanishka De Silva <[email protected]>
Reported-by Farhad Alemi <[email protected]>
Signed-off-by Namjae Jeon <[email protected]>
fs/smb/server/mgmt/share_config.c +27 -13
index b2d9580bddc6..cc9f18ede80d 100644
@@ -146,9 +146,9 @@ static struct ksmbd_share_config *__share_lookup(const char *name)
 
 static int parse_veto_list(struct ksmbd_share_config *share,
 			   char *veto_list,
-			   int veto_list_sz)
+			   size_t veto_list_sz)
 {
-	int sz = 0;
+	size_t sz;
 
 	if (!veto_list_sz)
 		return 0;

@@ -156,7 +156,7 @@ static int parse_veto_list(struct ksmbd_share_config *share,
 	while (veto_list_sz > 0) {
 		struct ksmbd_veto_pattern *p;
 
-		sz = strlen(veto_list);
+		sz = strnlen(veto_list, veto_list_sz);
 		if (!sz)
 			break;
 

@@ -164,7 +164,7 @@ static int parse_veto_list(struct ksmbd_share_config *share,
 		if (!p)
 			return -ENOMEM;
 
-		p->pattern = kstrdup(veto_list, KSMBD_DEFAULT_GFP);
+		p->pattern = kstrndup(veto_list, sz, KSMBD_DEFAULT_GFP);
 		if (!p->pattern) {
 			kfree(p);
 			return -ENOMEM;

@@ -172,6 +172,9 @@ static int parse_veto_list(struct ksmbd_share_config *share,
 
 		list_add(&p->list, &share->veto_list);
 
+		if (sz == veto_list_sz)
+			break;
+
 		veto_list += sz + 1;
 		veto_list_sz -= (sz + 1);
 	}

@@ -224,17 +227,28 @@ static struct ksmbd_share_config *share_config_request(struct ksmbd_work *work,
 	}
 
 	if (!test_share_config_flag(share, KSMBD_SHARE_FLAG_PIPE)) {
-		int path_len = PATH_MAX;
+		size_t path_len;
 
-		if (resp->payload_sz)
-			path_len = resp->payload_sz - resp->veto_list_sz;
-
-		share->path = kstrndup(ksmbd_share_config_path(resp), path_len,
-				      KSMBD_DEFAULT_GFP);
-		if (!share->path) {
-			ret = -ENOMEM;
+		if (resp->payload_sz <= resp->veto_list_sz) {
+			ret = -EINVAL;
 		} else {
-			ret = 0;
+			path_len = resp->payload_sz - resp->veto_list_sz;
+			if (resp->veto_list_sz)
+				path_len--;
+
+			if (!path_len) {
+				ret = -EINVAL;
+			} else {
+				share->path = kstrndup(
+					ksmbd_share_config_path(resp),
+					path_len, KSMBD_DEFAULT_GFP);
+				if (!share->path)
+					ret = -ENOMEM;
+				else
+					ret = 0;
+			}
+		}
+		if (share->path) {
 			share->path_sz = strlen(share->path);
 			while (share->path_sz > 1 &&
 			       share->path[share->path_sz - 1] == '/')
fs/smb/server/transport_ipc.c +14 -7
index 4b0b572a3e1b..e550aa41ad2c 100644
@@ -532,14 +532,21 @@ static int ipc_validate_msg(struct ipc_msg_table_entry *entry)
 		if (entry->msg_sz < sizeof(struct ksmbd_share_config_response))
 			return -EINVAL;
 
-		if (resp->payload_sz) {
-			if (resp->payload_sz < resp->veto_list_sz)
-				return -EINVAL;
+		if (strnlen(resp->share_name, sizeof(resp->share_name)) ==
+		    sizeof(resp->share_name))
+			return -EINVAL;
 
-			if (check_add_overflow(sizeof(struct ksmbd_share_config_response),
-					       resp->payload_sz, &msg_sz))
-				return -EINVAL;
-		}
+		if (resp->veto_list_sz > resp->payload_sz)
+			return -EINVAL;
+
+		if (resp->flags != KSMBD_SHARE_FLAG_INVALID &&
+		    !(resp->flags & KSMBD_SHARE_FLAG_PIPE) &&
+		    resp->payload_sz <= resp->veto_list_sz)
+			return -EINVAL;
+
+		if (check_add_overflow(sizeof(struct ksmbd_share_config_response),
+				       resp->payload_sz, &msg_sz))
+			return -EINVAL;
 		break;
 	}
 	case KSMBD_EVENT_LOGIN_REQUEST_EXT:
maintainer
#1 lore raw

PATCH 1/2 ksmbd: use __GFP_RETRY_MAYFAIL

From: Namjae Jeon <[email protected]>

[ Upstream commit 0066f623bce8f98b69b752ee03d46a5047c281b8 ]

Prefer to report ENOMEM rather than incur the oom for allocations in ksmbd. __GFP_NORETRY could not achieve that, It would fail the allocations just too easily. __GFP_RETRY_MAYFAIL will keep retrying the allocation until there is no more progress and fail the allocation instead go OOM and let the caller to deal with it.

Signed-off-by Namjae Jeon <[email protected]>
Signed-off-by Steve French <[email protected]>

Stable dependency adaptation for f25e93768fcc5d8287e50b1ec52a42e4c276df34:

Limit the allocation-flag conversion to share configuration and retain KSMBD_DEFAULT_GFP in glob.h. Drop the other subsystem conversions, which are unnecessary for the target and conflict with stable's existing ID, RPC locking, lease, ACL-buffer and network-interface implementations.

Include the existing-function share_config_request() error handling from a74668eb2c0b8 (path allocation failure) and the share_config.c changes from d2ccf905f47d2 (name allocation failure). These provide the target's patch context and ensure veto-list parsing cannot overwrite a failed path allocation or the target's invalid-path error. No functions are added.

[ sashal: Reduced backport -- upstream 0066f623bce8f touches 24 file(s), this
backport carries 2. Not backported here:
fs/smb/server/asn1.c
fs/smb/server/auth.c
fs/smb/server/connection.c
fs/smb/server/crypto_ctx.c
fs/smb/server/ksmbd_work.c
fs/smb/server/mgmt/ksmbd_ida.c fs/smb/server/mgmt/tree_connect.c fs/smb/server/mgmt/user_config.c
... and 14 more
This note is generated from the file lists only; see the resolution record for the reasoning. ]

Stable-dep-of: f25e93768fcc ("ksmbd: prevent out-of-bounds reads in share config responses")

Signed-off-by Sasha Levin <[email protected]>
---
 fs/smb/server/glob.h              |  2 ++
 fs/smb/server/mgmt/share_config.c | 29 +++++++++++++++++++----------
 2 files changed, 21 insertions(+), 10 deletions(-)
fs/smb/server/glob.h +2 -0
index 5b8f3e0ebdb36..3ce12b60e46fe 100644
@@ -46,4 +46,6 @@ extern int ksmbd_debug_types;
 
 #define UNICODE_LEN(x)		((x) * 2)
 
+#define KSMBD_DEFAULT_GFP	(GFP_KERNEL | __GFP_RETRY_MAYFAIL)
+
 #endif /* __KSMBD_GLOB_H */
fs/smb/server/mgmt/share_config.c +19 -10
index d8d03070ae44b..97b0bbd619979 100644
@@ -102,11 +102,11 @@ static int parse_veto_list(struct ksmbd_share_config *share,
 		if (!sz)
 			break;
 
-		p = kzalloc(sizeof(struct ksmbd_veto_pattern), GFP_KERNEL);
+		p = kzalloc(sizeof(struct ksmbd_veto_pattern), KSMBD_DEFAULT_GFP);
 		if (!p)
 			return -ENOMEM;
 
-		p->pattern = kstrdup(veto_list, GFP_KERNEL);
+		p->pattern = kstrdup(veto_list, KSMBD_DEFAULT_GFP);
 		if (!p->pattern) {
 			kfree(p);
 			return -ENOMEM;

@@ -150,14 +150,19 @@ static struct ksmbd_share_config *share_config_request(struct ksmbd_work *work,
 			goto out;
 	}
 
-	share = kzalloc(sizeof(struct ksmbd_share_config), GFP_KERNEL);
+	share = kzalloc(sizeof(struct ksmbd_share_config), KSMBD_DEFAULT_GFP);
 	if (!share)
 		goto out;
 
 	share->flags = resp->flags;
 	atomic_set(&share->refcount, 1);
 	INIT_LIST_HEAD(&share->veto_list);
-	share->name = kstrdup(name, GFP_KERNEL);
+	share->name = kstrdup(name, KSMBD_DEFAULT_GFP);
+	if (!share->name) {
+		kill_share(share);
+		share = NULL;
+		goto out;
+	}
 
 	if (!test_share_config_flag(share, KSMBD_SHARE_FLAG_PIPE)) {
 		int path_len = PATH_MAX;

@@ -166,8 +171,11 @@ static struct ksmbd_share_config *share_config_request(struct ksmbd_work *work,
 			path_len = resp->payload_sz - resp->veto_list_sz;
 
 		share->path = kstrndup(ksmbd_share_config_path(resp), path_len,
-				      GFP_KERNEL);
-		if (share->path) {
+				      KSMBD_DEFAULT_GFP);
+		if (!share->path) {
+			ret = -ENOMEM;
+		} else {
+			ret = 0;
 			share->path_sz = strlen(share->path);
 			while (share->path_sz > 1 &&
 			       share->path[share->path_sz - 1] == '/')

@@ -179,9 +187,10 @@ static struct ksmbd_share_config *share_config_request(struct ksmbd_work *work,
 		share->force_directory_mode = resp->force_directory_mode;
 		share->force_uid = resp->force_uid;
 		share->force_gid = resp->force_gid;
-		ret = parse_veto_list(share,
-				      KSMBD_SHARE_CONFIG_VETO_LIST(resp),
-				      resp->veto_list_sz);
+		if (!ret)
+			ret = parse_veto_list(share,
+					      KSMBD_SHARE_CONFIG_VETO_LIST(resp),
+					      resp->veto_list_sz);
 		if (!ret && share->path) {
 			if (__ksmbd_override_fsids(work, share)) {
 				kill_share(share);

@@ -199,7 +208,7 @@ static struct ksmbd_share_config *share_config_request(struct ksmbd_work *work,
 				share->path = NULL;
 			}
 		}
-		if (ret || !share->name) {
+		if (ret) {
 			kill_share(share);
 			share = NULL;
 			goto out;
Signature · 1 line
2.53.0
maintainer
#2 lore raw

PATCH 2/2 ksmbd: prevent out-of-bounds reads in share config responses

From: Namjae Jeon <[email protected]>

[ Upstream commit f25e93768fcc5d8287e50b1ec52a42e4c276df34 ]

Validate IPC share configuration payload sizes before consuming variable-length fields. Bound veto list parsing and account for the separator byte when deriving the path length.

Fixes a677ebd8ca2f ("ksmbd: validate payload size in ipc response")
Reported-by Kanishka De Silva <[email protected]>
Reported-by Farhad Alemi <[email protected]>
Signed-off-by Namjae Jeon <[email protected]>
Signed-off-by Sasha Levin <[email protected]>
---
 fs/smb/server/mgmt/share_config.c | 40 +++++++++++++++++++++----------
 fs/smb/server/transport_ipc.c     | 21 ++++++++++------
 2 files changed, 41 insertions(+), 20 deletions(-)
fs/smb/server/mgmt/share_config.c +27 -13
index 97b0bbd619979..e34e86cce0fc3 100644
@@ -88,9 +88,9 @@ static struct ksmbd_share_config *__share_lookup(const char *name)
 
 static int parse_veto_list(struct ksmbd_share_config *share,
 			   char *veto_list,
-			   int veto_list_sz)
+			   size_t veto_list_sz)
 {
-	int sz = 0;
+	size_t sz;
 
 	if (!veto_list_sz)
 		return 0;

@@ -98,7 +98,7 @@ static int parse_veto_list(struct ksmbd_share_config *share,
 	while (veto_list_sz > 0) {
 		struct ksmbd_veto_pattern *p;
 
-		sz = strlen(veto_list);
+		sz = strnlen(veto_list, veto_list_sz);
 		if (!sz)
 			break;
 

@@ -106,7 +106,7 @@ static int parse_veto_list(struct ksmbd_share_config *share,
 		if (!p)
 			return -ENOMEM;
 
-		p->pattern = kstrdup(veto_list, KSMBD_DEFAULT_GFP);
+		p->pattern = kstrndup(veto_list, sz, KSMBD_DEFAULT_GFP);
 		if (!p->pattern) {
 			kfree(p);
 			return -ENOMEM;

@@ -114,6 +114,9 @@ static int parse_veto_list(struct ksmbd_share_config *share,
 
 		list_add(&p->list, &share->veto_list);
 
+		if (sz == veto_list_sz)
+			break;
+
 		veto_list += sz + 1;
 		veto_list_sz -= (sz + 1);
 	}

@@ -165,17 +168,28 @@ static struct ksmbd_share_config *share_config_request(struct ksmbd_work *work,
 	}
 
 	if (!test_share_config_flag(share, KSMBD_SHARE_FLAG_PIPE)) {
-		int path_len = PATH_MAX;
-
-		if (resp->payload_sz)
-			path_len = resp->payload_sz - resp->veto_list_sz;
+		size_t path_len;
 
-		share->path = kstrndup(ksmbd_share_config_path(resp), path_len,
-				      KSMBD_DEFAULT_GFP);
-		if (!share->path) {
-			ret = -ENOMEM;
+		if (resp->payload_sz <= resp->veto_list_sz) {
+			ret = -EINVAL;
 		} else {
-			ret = 0;
+			path_len = resp->payload_sz - resp->veto_list_sz;
+			if (resp->veto_list_sz)
+				path_len--;
+
+			if (!path_len) {
+				ret = -EINVAL;
+			} else {
+				share->path = kstrndup(
+					ksmbd_share_config_path(resp),
+					path_len, KSMBD_DEFAULT_GFP);
+				if (!share->path)
+					ret = -ENOMEM;
+				else
+					ret = 0;
+			}
+		}
+		if (share->path) {
 			share->path_sz = strlen(share->path);
 			while (share->path_sz > 1 &&
 			       share->path[share->path_sz - 1] == '/')
fs/smb/server/transport_ipc.c +14 -7
index bbe039a05b1c3..80fd1316d176b 100644
@@ -524,14 +524,21 @@ static int ipc_validate_msg(struct ipc_msg_table_entry *entry)
 		if (entry->msg_sz < sizeof(struct ksmbd_share_config_response))
 			return -EINVAL;
 
-		if (resp->payload_sz) {
-			if (resp->payload_sz < resp->veto_list_sz)
-				return -EINVAL;
+		if (strnlen(resp->share_name, sizeof(resp->share_name)) ==
+		    sizeof(resp->share_name))
+			return -EINVAL;
 
-			if (check_add_overflow(sizeof(struct ksmbd_share_config_response),
-					       resp->payload_sz, &msg_sz))
-				return -EINVAL;
-		}
+		if (resp->veto_list_sz > resp->payload_sz)
+			return -EINVAL;
+
+		if (resp->flags != KSMBD_SHARE_FLAG_INVALID &&
+		    !(resp->flags & KSMBD_SHARE_FLAG_PIPE) &&
+		    resp->payload_sz <= resp->veto_list_sz)
+			return -EINVAL;
+
+		if (check_add_overflow(sizeof(struct ksmbd_share_config_response),
+				       resp->payload_sz, &msg_sz))
+			return -EINVAL;
 		break;
 	}
 	case KSMBD_EVENT_LOGIN_REQUEST_EXT:
Signature · 1 line
2.53.0