Author: jhb
Date: Fri Jul 23 14:30:31 2010
New Revision: 210413
URL: http://svn.freebsd.org/changeset/base/210413

Log:
  MFC 210066:
  Rework the SMBIOS table walker to make it operate like other table walkers
  and remove a buffer overflow.

Modified:
  stable/7/sys/dev/ipmi/ipmi_smbios.c
Directory Properties:
  stable/7/sys/   (props changed)
  stable/7/sys/cddl/contrib/opensolaris/   (props changed)
  stable/7/sys/contrib/dev/acpica/   (props changed)
  stable/7/sys/contrib/pf/   (props changed)

Modified: stable/7/sys/dev/ipmi/ipmi_smbios.c
==============================================================================
--- stable/7/sys/dev/ipmi/ipmi_smbios.c Fri Jul 23 14:30:14 2010        
(r210412)
+++ stable/7/sys/dev/ipmi/ipmi_smbios.c Fri Jul 23 14:30:31 2010        
(r210413)
@@ -52,7 +52,7 @@ __FBSDID("$FreeBSD$");
 #define        pmap_unmapbios          pmap_unmapdev
 #endif
 
-struct smbios_table_entry {
+struct smbios_table {
        uint8_t         anchor_string[4];
        uint8_t         checksum;
        uint8_t         length;
@@ -108,27 +108,30 @@ struct ipmi_entry {
 #define        SMBIOS_LEN              4
 #define        SMBIOS_SIG              "_SM_"
 
-typedef void (*dispatchproc_t)(uint8_t *p, char **table,
-    struct ipmi_get_info *info);
+typedef void (*smbios_callback_t)(struct structure_header *, void *);
 
 static struct ipmi_get_info ipmi_info;
 static int ipmi_probed;
 static struct mtx ipmi_info_mtx;
 MTX_SYSINIT(ipmi_info, &ipmi_info_mtx, "ipmi info", MTX_DEF);
 
-static char    *get_strings(char *, char **);
 static void    ipmi_smbios_probe(struct ipmi_get_info *);
-static int     smbios_cksum    (struct smbios_table_entry *);
-static void    smbios_run_table(uint8_t *, int, dispatchproc_t *,
-                   struct ipmi_get_info *);
-static void    smbios_t38_proc_info(uint8_t *, char **,
-                   struct ipmi_get_info *);
+static int     smbios_cksum(struct smbios_table *);
+static void    smbios_walk_table(uint8_t *, int, smbios_callback_t,
+                   void *);
+static void    smbios_ipmi_info(struct structure_header *, void *);
 
 static void
-smbios_t38_proc_info(uint8_t *p, char **table, struct ipmi_get_info *info)
+smbios_ipmi_info(struct structure_header *h, void *arg)
 {
-       struct ipmi_entry *s = (struct ipmi_entry *)p;
+       struct ipmi_get_info *info;
+       struct ipmi_entry *s;
 
+       if (h->type != 38 || h->length <
+           offsetof(struct ipmi_entry, interrupt_number))
+               return;
+       s = (struct ipmi_entry *)h;
+       info = arg;
        bzero(info, sizeof(struct ipmi_get_info));
        switch (s->interface_type) {
        case KCS_MODE:
@@ -172,44 +175,28 @@ smbios_t38_proc_info(uint8_t *p, char **
        info->iface_type = s->interface_type;
 }
 
-static char *
-get_strings(char *p, char **table)
-{
-       /* Scan for strings, stoping at a single null byte */
-       while (*p != 0) {
-               *table++ = p;
-               p += strlen(p) + 1;
-       }
-       *table = 0;
-
-       /* Skip past terminating null byte */
-       return (p + 1);
-}
-
-
 static void
-smbios_run_table(uint8_t *p, int entries, dispatchproc_t *dispatchstatus,
-    struct ipmi_get_info *info)
+smbios_walk_table(uint8_t *p, int entries, smbios_callback_t cb, void *arg)
 {
        struct structure_header *s;
-       char *table[20];
-       uint8_t *nextp;
 
-       while(entries--) {
-               s = (struct structure_header *) p;
-               nextp = get_strings(p + s->length, table);
+       while (entries--) {
+               s = (struct structure_header *)p;
+               cb(s, arg);
 
                /*
-                * No strings still has a double-null at the end,
-                * skip over it
+                * Look for a double-nul after the end of the
+                * formatted area of this structure.
                 */
-               if (table[0] == 0)
-                       nextp++;
+               p += s->length;
+               while (p[0] != 0 && p[1] != 0)
+                       p++;
 
-               if (dispatchstatus[*p]) {
-                       (dispatchstatus[*p])(p, table, info);
-               }
-               p = nextp;
+               /*
+                * Skip over the double-nul to the start of the next
+                * structure.
+                */
+               p += 2;
        }
 }
 
@@ -221,8 +208,7 @@ smbios_run_table(uint8_t *p, int entries
 static void
 ipmi_smbios_probe(struct ipmi_get_info *info)
 {
-       dispatchproc_t dispatch_smbios_ipmi[256];
-       struct smbios_table_entry *header;
+       struct smbios_table *header;
        void *table;
        u_int32_t addr;
 
@@ -239,9 +225,9 @@ ipmi_smbios_probe(struct ipmi_get_info *
         * length and then map it a second time with the actual length so
         * we can verify the checksum.
         */
-       header = pmap_mapbios(addr, sizeof(struct smbios_table_entry));
+       header = pmap_mapbios(addr, sizeof(struct smbios_table));
        table = pmap_mapbios(addr, header->length);
-       pmap_unmapbios((vm_offset_t)header, sizeof(struct smbios_table_entry));
+       pmap_unmapbios((vm_offset_t)header, sizeof(struct smbios_table));
        header = table;
        if (smbios_cksum(header) != 0) {
                pmap_unmapbios((vm_offset_t)header, header->length);
@@ -251,9 +237,7 @@ ipmi_smbios_probe(struct ipmi_get_info *
        /* Now map the actual table and walk it looking for an IPMI entry. */
        table = pmap_mapbios(header->structure_table_address,
            header->structure_table_length);
-       bzero((void *)dispatch_smbios_ipmi, sizeof(dispatch_smbios_ipmi));
-       dispatch_smbios_ipmi[38] = (void *)smbios_t38_proc_info;
-       smbios_run_table(table, header->number_structures, dispatch_smbios_ipmi,
+       smbios_walk_table(table, header->number_structures, smbios_ipmi_info,
            info);
 
        /* Unmap everything. */
@@ -298,7 +282,7 @@ ipmi_smbios_identify(struct ipmi_get_inf
 }
 
 static int
-smbios_cksum (struct smbios_table_entry *e)
+smbios_cksum(struct smbios_table *e)
 {
        u_int8_t *ptr;
        u_int8_t cksum;
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