[PATCH] rock: handle directory overflows

Handle the case where the variable-sized part of a rock-ridge directory entry
overhangs the end of the buffer which we allocated for it.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 74 insertions, 2 deletions

diff --git a/fs/isofs/rock.c b/fs/isofs/rock.c
index 9a81830abff8..4326cb47f8fa 100644
--- a/fs/isofs/rock.c
+++ b/fs/isofs/rock.c
@@ -127,6 +127,66 @@ out:
 }
 
 /*
+ * We think there's a record of type `sig' at rs->chr.  Parse the signature
+ * and make sure that there's really room for a record of that type.
+ */
+static int rock_check_overflow(struct rock_state *rs, int sig)
+{
+        int len;
+
+        switch (sig) {
+        case SIG('S', 'P'):
+                len = sizeof(struct SU_SP_s);
+                break;
+        case SIG('C', 'E'):
+                len = sizeof(struct SU_CE_s);
+                break;
+        case SIG('E', 'R'):
+                len = sizeof(struct SU_ER_s);
+                break;
+        case SIG('R', 'R'):
+                len = sizeof(struct RR_RR_s);
+                break;
+        case SIG('P', 'X'):
+                len = sizeof(struct RR_PX_s);
+                break;
+        case SIG('P', 'N'):
+                len = sizeof(struct RR_PN_s);
+                break;
+        case SIG('S', 'L'):
+                len = sizeof(struct RR_SL_s);
+                break;
+        case SIG('N', 'M'):
+                len = sizeof(struct RR_NM_s);
+                break;
+        case SIG('C', 'L'):
+                len = sizeof(struct RR_CL_s);
+                break;
+        case SIG('P', 'L'):
+                len = sizeof(struct RR_PL_s);
+                break;
+        case SIG('T', 'F'):
+                len = sizeof(struct RR_TF_s);
+                break;
+        case SIG('Z', 'F'):
+                len = sizeof(struct RR_ZF_s);
+                break;
+        default:
+                len = 0;
+                break;
+        }
+        len += offsetof(struct rock_ridge, u);
+        if (len > rs->len) {
+                printk(KERN_NOTICE "rock: directory entry would overflow "
+                                "storage\n");
+                printk(KERN_NOTICE "rock: sig=0x%02x, size=%d, remaining=%d\n",
+                                sig, len, rs->len);
+                return -EIO;
+        }
+        return 0;
+}
+
+/*
  * return length of name field; 0: not found, -1: to be ignored
  */
 int get_rock_ridge_filename(struct iso_directory_record *de,
@@ -152,10 +212,12 @@ repeat:
                 if (rr->len < 3)
                         goto out;       /* Something got screwed up here */
                 sig = isonum_721(rs.chr);
+                if (rock_check_overflow(&rs, sig))
+                        goto eio;
                 rs.chr += rr->len;
                 rs.len -= rr->len;
                 if (rs.len < 0)
-                        goto out;       /* corrupted isofs */
+                        goto eio;       /* corrupted isofs */
 
                 switch (sig) {
                 case SIG('R', 'R'):
@@ -213,6 +275,9 @@ repeat:
 out:
         kfree(rs.buffer);
         return ret;
+eio:
+        ret = -EIO;
+        goto out;
 }
 
 static int
@@ -245,10 +310,12 @@ repeat:
                 if (rr->len < 3)
                         goto out;       /* Something got screwed up here */
                 sig = isonum_721(rs.chr);
+                if (rock_check_overflow(&rs, sig))
+                        goto eio;
                 rs.chr += rr->len;
                 rs.len -= rr->len;
                 if (rs.len < 0)
-                        goto out;       /* corrupted isofs */
+                        goto eio;       /* corrupted isofs */
 
                 switch (sig) {
 #ifndef CONFIG_ZISOFS           /* No flag for SF or ZF */
@@ -479,6 +546,9 @@ repeat:
 out:
         kfree(rs.buffer);
         return ret;
+eio:
+        ret = -EIO;
+        goto out;
 }
 
 static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr, char *plimit)
@@ -618,6 +688,8 @@ repeat:
                 if (rr->len < 3)
                         goto out;       /* Something got screwed up here */
                 sig = isonum_721(rs.chr);
+                if (rock_check_overflow(&rs, sig))
+                        goto out;
                 rs.chr += rr->len;
                 rs.len -= rr->len;
                 if (rs.len < 0)