From: David S. Miller
> From: "Kris Katterjohn" <[EMAIL PROTECTED]>
> Your email client has corrupted the patch spacing and tabbing.
> Please fix this.
Really? Have my other patches been screwed up, too? My email client has
"upgraded" recently (although I'm not sure what it was supposed to be updating),
so I'm sending this one from the old web-based version. It should work because I
sent my other patches through this one.
It won't be a problem for me to send the patch as an attachment if this one
screws up, will it?
Sorry about this.
Signed-off-by: Kris Katterjohn <[EMAIL PROTECTED]>
--- x/net/core/filter.c 2006-01-03 11:09:07.000000000 -0600
+++ y/net/core/filter.c 2006-01-03 21:42:02.000000000 -0600
@@ -13,6 +13,7 @@
* 2 of the License, or (at your option) any later version.
*
* Andi Kleen - Fix a few bad bugs and races.
+ * Kris Katterjohn - Added many additional checks in sk_chk_filter()
*/
#include <linux/module.h>
@@ -250,7 +251,7 @@ load_b:
mem[fentry->k] = X;
continue;
default:
- /* Invalid instruction counts as RET */
+ WARN_ON(1);
return 0;
}
@@ -283,8 +284,8 @@ load_b:
*
* Check the user's filter code. If we let some ugly
* filter code slip through kaboom! The filter must contain
- * no references or jumps that are out of range, no illegal instructions
- * and no backward jumps. It must end with a RET instruction
+ * no references or jumps that are out of range, no illegal
+ * instructions, and must end with a RET instruction.
*
* Returns 0 if the rule set is legal or a negative errno code if not.
*/
@@ -300,38 +301,85 @@ int sk_chk_filter(struct sock_filter *fi
for (pc = 0; pc < flen; pc++) {
/* all jumps are forward as they are not signed */
ftest = &filter[pc];
- if (BPF_CLASS(ftest->code) == BPF_JMP) {
- /* but they mustn't jump off the end */
- if (BPF_OP(ftest->code) == BPF_JA) {
- /*
- * Note, the large ftest->k might cause loops.
- * Compare this with conditional jumps below,
- * where offsets are limited. --ANK (981016)
- */
- if (ftest->k >= (unsigned)(flen-pc-1))
- return -EINVAL;
- } else {
- /* for conditionals both must be safe */
- if (pc + ftest->jt +1 >= flen ||
- pc + ftest->jf +1 >= flen)
- return -EINVAL;
- }
- }
- /* check for division by zero -Kris Katterjohn 2005-10-30 */
- if (ftest->code == (BPF_ALU|BPF_DIV|BPF_K) && ftest->k == 0)
- return -EINVAL;
+ /* Only allow valid instructions */
+ switch (ftest->code) {
+ case BPF_ALU|BPF_ADD|BPF_K:
+ case BPF_ALU|BPF_ADD|BPF_X:
+ case BPF_ALU|BPF_SUB|BPF_K:
+ case BPF_ALU|BPF_SUB|BPF_X:
+ case BPF_ALU|BPF_MUL|BPF_K:
+ case BPF_ALU|BPF_MUL|BPF_X:
+ case BPF_ALU|BPF_DIV|BPF_X:
+ case BPF_ALU|BPF_AND|BPF_K:
+ case BPF_ALU|BPF_AND|BPF_X:
+ case BPF_ALU|BPF_OR|BPF_K:
+ case BPF_ALU|BPF_OR|BPF_X:
+ case BPF_ALU|BPF_LSH|BPF_K:
+ case BPF_ALU|BPF_LSH|BPF_X:
+ case BPF_ALU|BPF_RSH|BPF_K:
+ case BPF_ALU|BPF_RSH|BPF_X:
+ case BPF_ALU|BPF_NEG:
+ case BPF_LD|BPF_W|BPF_ABS:
+ case BPF_LD|BPF_H|BPF_ABS:
+ case BPF_LD|BPF_B|BPF_ABS:
+ case BPF_LD|BPF_W|BPF_LEN:
+ case BPF_LD|BPF_W|BPF_IND:
+ case BPF_LD|BPF_H|BPF_IND:
+ case BPF_LD|BPF_B|BPF_IND:
+ case BPF_LD|BPF_IMM:
+ case BPF_LDX|BPF_W|BPF_LEN:
+ case BPF_LDX|BPF_B|BPF_MSH:
+ case BPF_LDX|BPF_IMM:
+ case BPF_MISC|BPF_TAX:
+ case BPF_MISC|BPF_TXA:
+ case BPF_RET|BPF_K:
+ case BPF_RET|BPF_A:
+ break;
+
+ /* Some instructions need special checks */
- /* check that memory operations use valid addresses. */
- if (ftest->k >= BPF_MEMWORDS) {
- /* but it might not be a memory operation... */
- switch (ftest->code) {
- case BPF_ST:
- case BPF_STX:
- case BPF_LD|BPF_MEM:
- case BPF_LDX|BPF_MEM:
+ case BPF_ALU|BPF_DIV|BPF_K:
+ /* check for division by zero */
+ if (ftest->k == 0)
return -EINVAL;
- }
+ break;
+
+ case BPF_LD|BPF_MEM:
+ case BPF_LDX|BPF_MEM:
+ case BPF_ST:
+ case BPF_STX:
+ /* check for invalid memory addresses */
+ if (ftest->k >= BPF_MEMWORDS)
+ return -EINVAL;
+ break;
+
+ case BPF_JMP|BPF_JA:
+ /*
+ * Note, the large ftest->k might cause loops.
+ * Compare this with conditional jumps below,
+ * where offsets are limited. --ANK (981016)
+ */
+ if (ftest->k >= (unsigned)(flen-pc-1))
+ return -EINVAL;
+ break;
+
+ case BPF_JMP|BPF_JEQ|BPF_K:
+ case BPF_JMP|BPF_JEQ|BPF_X:
+ case BPF_JMP|BPF_JGE|BPF_K:
+ case BPF_JMP|BPF_JGE|BPF_X:
+ case BPF_JMP|BPF_JGT|BPF_K:
+ case BPF_JMP|BPF_JGT|BPF_X:
+ case BPF_JMP|BPF_JSET|BPF_K:
+ case BPF_JMP|BPF_JSET|BPF_X:
+ /* for conditionals both must be safe */
+ if (pc + ftest->jt + 1 >= flen ||
+ pc + ftest->jf + 1 >= flen)
+ return -EINVAL;
+ break;
+
+ default:
+ return -EINVAL;
}
}
-
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