3.18-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 92a8109e4d3a34fb6b115c9098b51767dc933444 ]
The code tries to allocate a contiguous buffer with a size supplied by the server (maxBuf). This could fail if memory is fragmented since it results in high order allocations for commonly used server implementations. It is also wasteful since there are probably few locks in the usual case. Limit the buffer to be no larger than a page to avoid memory allocation failures due to fragmentation.
Signed-off-by: Ross Lagerwall ross.lagerwall@citrix.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/cifs/file.c | 8 ++++++++ fs/cifs/smb2file.c | 4 ++++ 2 files changed, 12 insertions(+)
--- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -1075,6 +1075,10 @@ cifs_push_mandatory_locks(struct cifsFil return -EINVAL; }
+ BUILD_BUG_ON(sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE) > + PAGE_SIZE); + max_buf = min_t(unsigned int, max_buf - sizeof(struct smb_hdr), + PAGE_SIZE); max_num = (max_buf - sizeof(struct smb_hdr)) / sizeof(LOCKING_ANDX_RANGE); buf = kzalloc(max_num * sizeof(LOCKING_ANDX_RANGE), GFP_KERNEL); @@ -1410,6 +1414,10 @@ cifs_unlock_range(struct cifsFileInfo *c if (max_buf < (sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE))) return -EINVAL;
+ BUILD_BUG_ON(sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE) > + PAGE_SIZE); + max_buf = min_t(unsigned int, max_buf - sizeof(struct smb_hdr), + PAGE_SIZE); max_num = (max_buf - sizeof(struct smb_hdr)) / sizeof(LOCKING_ANDX_RANGE); buf = kzalloc(max_num * sizeof(LOCKING_ANDX_RANGE), GFP_KERNEL); --- a/fs/cifs/smb2file.c +++ b/fs/cifs/smb2file.c @@ -110,6 +110,8 @@ smb2_unlock_range(struct cifsFileInfo *c if (max_buf < sizeof(struct smb2_lock_element)) return -EINVAL;
+ BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE); + max_buf = min_t(unsigned int, max_buf, PAGE_SIZE); max_num = max_buf / sizeof(struct smb2_lock_element); buf = kzalloc(max_num * sizeof(struct smb2_lock_element), GFP_KERNEL); if (!buf) @@ -246,6 +248,8 @@ smb2_push_mandatory_locks(struct cifsFil return -EINVAL; }
+ BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE); + max_buf = min_t(unsigned int, max_buf, PAGE_SIZE); max_num = max_buf / sizeof(struct smb2_lock_element); buf = kzalloc(max_num * sizeof(struct smb2_lock_element), GFP_KERNEL); if (!buf) {