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authorRoss Lagerwall <ross.lagerwall@citrix.com>2019-01-08 18:30:56 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-02-20 10:13:21 +0100
commit1f39e518cf9190422119a53a6d6964e800e7e789 (patch)
treed8c3556c2b54df7e7f0bda31cdaeb651e696b267
parent8347670127511f031d2e3503ae00a25d1956f19b (diff)
cifs: Limit memory used by lock request calls to a page
[ 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>
-rw-r--r--fs/cifs/file.c8
-rw-r--r--fs/cifs/smb2file.c4
2 files changed, 12 insertions, 0 deletions
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 026b399af215..1062e96ee272 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1081,6 +1081,10 @@ cifs_push_mandatory_locks(struct cifsFileInfo *cfile)
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 = kcalloc(max_num, sizeof(LOCKING_ANDX_RANGE), GFP_KERNEL);
@@ -1410,6 +1414,10 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
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 = kcalloc(max_num, sizeof(LOCKING_ANDX_RANGE), GFP_KERNEL);
diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
index b7885dc0d9bb..dee5250701de 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -129,6 +129,8 @@ smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
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 = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
if (!buf)
@@ -265,6 +267,8 @@ smb2_push_mandatory_locks(struct cifsFileInfo *cfile)
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 = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
if (!buf) {