From: Jan Kara jack@suse.cz
When new directory 'DIR1' is created in a directory 'DIR0' with SGID bit set, DIR1 is expected to have SGID bit set (and owning group equal to the owning group of 'DIR0'). However when 'DIR0' also has some default ACLs that 'DIR1' inherits, setting these ACLs will result in SGID bit on 'DIR1' to get cleared if user is not member of the owning group.
Fix the problem by moving posix_acl_update_mode() out of __btrfs_set_acl() into btrfs_set_acl(). That way the function will not be called when inheriting ACLs which is what we want as it prevents SGID bit clearing and the mode has been properly set by posix_acl_create() anyway.
Fixes: 073931017b49d9458aa351605b43a7e34598caef CC: stable@vger.kernel.org CC: linux-btrfs@vger.kernel.org CC: David Sterba dsterba@suse.com Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Nikolay Borisov nborisov@suse.com --- fs/btrfs/acl.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c index fb3e64d37cb4..233bbc8789e0 100644 --- a/fs/btrfs/acl.c +++ b/fs/btrfs/acl.c @@ -82,12 +82,6 @@ static int __btrfs_set_acl(struct btrfs_trans_handle *trans, switch (type) { case ACL_TYPE_ACCESS: name = POSIX_ACL_XATTR_ACCESS; - if (acl) { - ret = posix_acl_update_mode(inode, &inode->i_mode, &acl); - if (ret) - return ret; - } - ret = 0; break; case ACL_TYPE_DEFAULT: if (!S_ISDIR(inode->i_mode)) @@ -123,6 +117,13 @@ static int __btrfs_set_acl(struct btrfs_trans_handle *trans,
int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) { + int ret; + + if (type == ACL_TYPE_ACCESS && acl) { + ret = posix_acl_update_mode(inode, &inode->i_mode, &acl); + if (ret) + return ret; + } return __btrfs_set_acl(NULL, inode, acl, type); }
From: Ernesto A. Fernández ernesto.mnd.fernandez@gmail.com
When changing a file's acl mask, btrfs_set_acl() will first set the group bits of i_mode to the value of the mask, and only then set the actual extended attribute representing the new acl.
If the second part fails (due to lack of space, for example) and the file had no acl attribute to begin with, the system will from now on assume that the mask permission bits are actual group permission bits, potentially granting access to the wrong users.
Prevent this by restoring the original mode bits if __btrfs_set_acl fails.
Signed-off-by: Ernesto A. Fernández ernesto.mnd.fernandez@gmail.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Acked-by: Nikolay Borisov nborisov@suse.com Signed-off-by: Nikolay Borisov nborisov@suse.com --- fs/btrfs/acl.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c index 233bbc8789e0..6b16b8653d98 100644 --- a/fs/btrfs/acl.c +++ b/fs/btrfs/acl.c @@ -118,13 +118,17 @@ static int __btrfs_set_acl(struct btrfs_trans_handle *trans, int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) { int ret; + umode_t old_mode = inode->i_mode;
if (type == ACL_TYPE_ACCESS && acl) { ret = posix_acl_update_mode(inode, &inode->i_mode, &acl); if (ret) return ret; } - return __btrfs_set_acl(NULL, inode, acl, type); + ret = __btrfs_set_acl(NULL, inode, acl, type); + if (ret) + inode->i_mode = old_mode; + return ret; }
/*
Your subject is odd :(
On Wed, Mar 07, 2018 at 09:57:24AM +0200, Nikolay Borisov wrote:
From: Ernesto A. Fernández ernesto.mnd.fernandez@gmail.com
When changing a file's acl mask, btrfs_set_acl() will first set the group bits of i_mode to the value of the mask, and only then set the actual extended attribute representing the new acl.
If the second part fails (due to lack of space, for example) and the file had no acl attribute to begin with, the system will from now on assume that the mask permission bits are actual group permission bits, potentially granting access to the wrong users.
Prevent this by restoring the original mode bits if __btrfs_set_acl fails.
Signed-off-by: Ernesto A. Fernández ernesto.mnd.fernandez@gmail.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Acked-by: Nikolay Borisov nborisov@suse.com Signed-off-by: Nikolay Borisov nborisov@suse.com
fs/btrfs/acl.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
What is the git commit id of this patch, and the previous patch in this series?
thanks,
greg k-h
On Wed, Mar 07, 2018 at 09:57:24AM +0200, Nikolay Borisov wrote:
From: Ernesto A. Fernández ernesto.mnd.fernandez@gmail.com
When changing a file's acl mask, btrfs_set_acl() will first set the group bits of i_mode to the value of the mask, and only then set the actual extended attribute representing the new acl.
If the second part fails (due to lack of space, for example) and the file had no acl attribute to begin with, the system will from now on assume that the mask permission bits are actual group permission bits, potentially granting access to the wrong users.
Prevent this by restoring the original mode bits if __btrfs_set_acl fails.
Signed-off-by: Ernesto A. Fernández ernesto.mnd.fernandez@gmail.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Acked-by: Nikolay Borisov nborisov@suse.com Signed-off-by: Nikolay Borisov nborisov@suse.com
fs/btrfs/acl.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
Shouldn't this also be added to 4.9.y?
thanks,
greg k-h
From: Ernesto A. Fernández ernesto.mnd.fernandez@gmail.com
When changing a file's acl mask, btrfs_set_acl() will first set the group bits of i_mode to the value of the mask, and only then set the actual extended attribute representing the new acl.
If the second part fails (due to lack of space, for example) and the file had no acl attribute to begin with, the system will from now on assume that the mask permission bits are actual group permission bits, potentially granting access to the wrong users.
Prevent this by restoring the original mode bits if __btrfs_set_acl fails.
Signed-off-by: Ernesto A. Fernández ernesto.mnd.fernandez@gmail.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Nikolay Borisov nborisov@suse.com --- fs/btrfs/acl.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c index 8d8370ddb6b2..1ba49ebe67da 100644 --- a/fs/btrfs/acl.c +++ b/fs/btrfs/acl.c @@ -114,13 +114,17 @@ static int __btrfs_set_acl(struct btrfs_trans_handle *trans, int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) { int ret; + umode_t old_mode = inode->i_mode;
if (type == ACL_TYPE_ACCESS && acl) { ret = posix_acl_update_mode(inode, &inode->i_mode, &acl); if (ret) return ret; } - return __btrfs_set_acl(NULL, inode, acl, type); + ret = __btrfs_set_acl(NULL, inode, acl, type); + if (ret) + inode->i_mode = old_mode; + return ret; }
/*
On Fri, Mar 09, 2018 at 10:17:43AM +0200, Nikolay Borisov wrote:
From: Ernesto A. Fernández ernesto.mnd.fernandez@gmail.com
When changing a file's acl mask, btrfs_set_acl() will first set the group bits of i_mode to the value of the mask, and only then set the actual extended attribute representing the new acl.
If the second part fails (due to lack of space, for example) and the file had no acl attribute to begin with, the system will from now on assume that the mask permission bits are actual group permission bits, potentially granting access to the wrong users.
Prevent this by restoring the original mode bits if __btrfs_set_acl fails.
Signed-off-by: Ernesto A. Fernández ernesto.mnd.fernandez@gmail.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Nikolay Borisov nborisov@suse.com
fs/btrfs/acl.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c index 8d8370ddb6b2..1ba49ebe67da 100644 --- a/fs/btrfs/acl.c +++ b/fs/btrfs/acl.c @@ -114,13 +114,17 @@ static int __btrfs_set_acl(struct btrfs_trans_handle *trans, int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) { int ret;
- umode_t old_mode = inode->i_mode;
if (type == ACL_TYPE_ACCESS && acl) { ret = posix_acl_update_mode(inode, &inode->i_mode, &acl); if (ret) return ret; }
- return __btrfs_set_acl(NULL, inode, acl, type);
- ret = __btrfs_set_acl(NULL, inode, acl, type);
- if (ret)
inode->i_mode = old_mode;- return ret;
} /* -- 2.7.4
Thanks for the patches, all now queued up.
greg k-h
On 7.03.2018 09:57, Nikolay Borisov wrote:
From: Jan Kara jack@suse.cz
When new directory 'DIR1' is created in a directory 'DIR0' with SGID bit set, DIR1 is expected to have SGID bit set (and owning group equal to the owning group of 'DIR0'). However when 'DIR0' also has some default ACLs that 'DIR1' inherits, setting these ACLs will result in SGID bit on 'DIR1' to get cleared if user is not member of the owning group.
Fix the problem by moving posix_acl_update_mode() out of __btrfs_set_acl() into btrfs_set_acl(). That way the function will not be called when inheriting ACLs which is what we want as it prevents SGID bit clearing and the mode has been properly set by posix_acl_create() anyway.
Fixes: 073931017b49d9458aa351605b43a7e34598caef CC: stable@vger.kernel.org CC: linux-btrfs@vger.kernel.org CC: David Sterba dsterba@suse.com Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Nikolay Borisov nborisov@suse.com
Geez, forgot to add the in-reply-to for proper threading. Anyways, those are the two backports I emailed you yesterday about.
fs/btrfs/acl.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c index fb3e64d37cb4..233bbc8789e0 100644 --- a/fs/btrfs/acl.c +++ b/fs/btrfs/acl.c @@ -82,12 +82,6 @@ static int __btrfs_set_acl(struct btrfs_trans_handle *trans, switch (type) { case ACL_TYPE_ACCESS: name = POSIX_ACL_XATTR_ACCESS;
if (acl) {ret = posix_acl_update_mode(inode, &inode->i_mode, &acl);if (ret)return ret;}ret = 0;@@ -123,6 +117,13 @@ static int __btrfs_set_acl(struct btrfs_trans_handle *trans, int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) {
- int ret;
- if (type == ACL_TYPE_ACCESS && acl) {
ret = posix_acl_update_mode(inode, &inode->i_mode, &acl);if (ret)return ret;- } return __btrfs_set_acl(NULL, inode, acl, type);
}
linux-stable-mirror@lists.linaro.org
-
Greg KH -
Nikolay Borisov