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cifs: fix SID binary to string conversion

The authority fields are supposed to be represented by a single 48-bit
value. It's also supposed to represent the value as hex if it's equal to
or greater than 2^32. This is documented in MS-DTYP, section 2.4.2.1.

Also, fix up the max string length to account for this fix.

Acked-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
master
Jeff Layton 9 years ago
committed by Steve French
parent
commit
193cdd8a29
  1. 25
      fs/cifs/cifsacl.c
  2. 8
      fs/cifs/cifsacl.h

25
fs/cifs/cifsacl.c

@ -94,6 +94,7 @@ sid_to_key_str(struct cifs_sid *sidptr, unsigned int type)
int i, len;
unsigned int saval;
char *sidstr, *strptr;
unsigned long long id_auth_val;
/* 3 bytes for prefix */
sidstr = kmalloc(3 + SID_STRING_BASE_SIZE +
@ -107,12 +108,24 @@ sid_to_key_str(struct cifs_sid *sidptr, unsigned int type)
sidptr->revision);
strptr += len;
for (i = 0; i < NUM_AUTHS; ++i) {
if (sidptr->authority[i]) {
len = sprintf(strptr, "-%hhu", sidptr->authority[i]);
strptr += len;
}
}
/* The authority field is a single 48-bit number */
id_auth_val = (unsigned long long)sidptr->authority[5];
id_auth_val |= (unsigned long long)sidptr->authority[4] << 8;
id_auth_val |= (unsigned long long)sidptr->authority[3] << 16;
id_auth_val |= (unsigned long long)sidptr->authority[2] << 24;
id_auth_val |= (unsigned long long)sidptr->authority[1] << 32;
id_auth_val |= (unsigned long long)sidptr->authority[0] << 48;
/*
* MS-DTYP states that if the authority is >= 2^32, then it should be
* expressed as a hex value.
*/
if (id_auth_val <= UINT_MAX)
len = sprintf(strptr, "-%llu", id_auth_val);
else
len = sprintf(strptr, "-0x%llx", id_auth_val);
strptr += len;
for (i = 0; i < sidptr->num_subauth; ++i) {
saval = le32_to_cpu(sidptr->sub_auth[i]);

8
fs/cifs/cifsacl.h

@ -55,12 +55,14 @@
* u8: max 3 bytes in decimal
* u32: max 10 bytes in decimal
*
* "S-" + 3 bytes for version field + 4 bytes for each authority field (3 bytes
* per number + 1 for '-') + NULL terminator.
* "S-" + 3 bytes for version field + 15 for authority field + NULL terminator
*
* For authority field, max is when all 6 values are non-zero and it must be
* represented in hex. So "-0x" + 12 hex digits.
*
* Add 11 bytes for each subauthority field (10 bytes each + 1 for '-')
*/
#define SID_STRING_BASE_SIZE (2 + 3 + (4 * NUM_AUTHS) + 1)
#define SID_STRING_BASE_SIZE (2 + 3 + 15 + 1)
#define SID_STRING_SUBAUTH_SIZE (11) /* size of a single subauth string */
struct cifs_ntsd {

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