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authorRoss Lagerwall <ross.lagerwall@citrix.com>2019-01-08 18:30:56 +0000
committerSteve French <stfrench@microsoft.com>2019-01-11 07:14:40 -0600
commit92a8109e4d3a34fb6b115c9098b51767dc933444 (patch)
treebf25221c25731b147937ae58efdf15c54be3e19a
parent15bc77f94e9f0e3cfd6972f3b84bb7aaa4c36b1b (diff)
downloadlinux-92a8109e4d3a34fb6b115c9098b51767dc933444.tar.bz2
cifs: Limit memory used by lock request calls to a page
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>
-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 e3e3a7550205..673f948e4760 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1140,6 +1140,10 @@ 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);
@@ -1478,6 +1482,10 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
if (!max_buf)
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 4ed10dd086e6..eff01ed6db0a 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -128,6 +128,8 @@ smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
if (!max_buf)
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)
@@ -264,6 +266,8 @@ 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) {