[CIFS] Fix acl length when very short ACL being modified by chmod

Signed-off-by: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index 1cb5b0a9f2aca95b8790a8b6be3fae90157f9e68..e99d4faf5f022e5c3315dbd38b63e12e85ccf0e7 100644 (file)
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -516,7 +516,7 @@ static int parse_sec_desc(struct cifs_ntsd *pntsd, int acl_len,
 
 /* Convert permission bits from mode to equivalent CIFS ACL */
 static int build_sec_desc(struct cifs_ntsd *pntsd, struct cifs_ntsd *pnntsd,
-                               int acl_len, struct inode *inode, __u64 nmode)
+                               struct inode *inode, __u64 nmode)
 {
        int rc = 0;
        __u32 dacloffset;
@@ -692,14 +692,14 @@ void acl_to_uid_mode(struct inode *inode, const char *path, const __u16 *pfid)
 int mode_to_acl(struct inode *inode, const char *path, __u64 nmode)
 {
        int rc = 0;
-       __u32 acllen = 0;
+       __u32 secdesclen = 0;
        struct cifs_ntsd *pntsd = NULL; /* acl obtained from server */
        struct cifs_ntsd *pnntsd = NULL; /* modified acl to be sent to server */
 
        cFYI(DBG2, ("set ACL from mode for %s", path));
 
        /* Get the security descriptor */
-       pntsd = get_cifs_acl(&acllen, inode, path, NULL);
+       pntsd = get_cifs_acl(&secdesclen, inode, path, NULL);
 
        /* Add three ACEs for owner, group, everyone getting rid of
           other ACEs as chmod disables ACEs and set the security descriptor */
@@ -709,20 +709,22 @@ int mode_to_acl(struct inode *inode, const char *path, __u64 nmode)
                   set security descriptor request security descriptor
                   parameters, and secuirty descriptor itself */
 
-               pnntsd = kmalloc(acllen, GFP_KERNEL);
+               secdesclen = secdesclen < DEFSECDESCLEN ?
+                                       DEFSECDESCLEN : secdesclen;
+               pnntsd = kmalloc(secdesclen, GFP_KERNEL);
                if (!pnntsd) {
                        cERROR(1, ("Unable to allocate security descriptor"));
                        kfree(pntsd);
                        return (-ENOMEM);
                }
 
-               rc = build_sec_desc(pntsd, pnntsd, acllen, inode, nmode);
+               rc = build_sec_desc(pntsd, pnntsd, inode, nmode);
 
                cFYI(DBG2, ("build_sec_desc rc: %d", rc));
 
                if (!rc) {
                        /* Set the security descriptor */
-                       rc = set_cifs_acl(pnntsd, acllen, inode, path);
+                       rc = set_cifs_acl(pnntsd, secdesclen, inode, path);
                        cFYI(DBG2, ("set_cifs_acl rc: %d", rc));
                }
 

diff --git a/fs/cifs/cifsacl.h b/fs/cifs/cifsacl.h
index 93a7c3462ea27c7c3080bbc963f545ba51fe1286..6c8096cf51557764aa10af6c28d108d3e93ce6e7 100644 (file)
--- a/fs/cifs/cifsacl.h
+++ b/fs/cifs/cifsacl.h
@@ -27,6 +27,7 @@
 #define NUM_SUBAUTHS 5 /* number of sub authority fields */
 #define NUM_WK_SIDS 7 /* number of well known sids */
 #define SIDNAMELENGTH 20 /* long enough for the ones we care about */
+#define DEFSECDESCLEN 192 /* sec desc len contaiting a dacl with three aces */
 
 #define READ_BIT        0x4
 #define WRITE_BIT       0x2