[-mm patch] binfmt_elf: fix checks for bad address

[Chuck Ebbert]

Fix check for bad address; use macro instead of open-coding two checks.

Taken from RHEL4 kernel update.

Signed-off-by: Chuck Ebbert <76306.1226@xxxxxxxxxxxxxx>

--- 2.6.17-32.orig/fs/binfmt_elf.c
+++ 2.6.17-32/fs/binfmt_elf.c
@@ -84,7 +84,7 @@ static struct linux_binfmt elf_format = 
 		.min_coredump	= ELF_EXEC_PAGESIZE
 };
 
-#define BAD_ADDR(x) ((unsigned long)(x) > TASK_SIZE)
+#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
 
 static int set_brk(unsigned long start, unsigned long end)
 {
@@ -394,7 +394,7 @@ static unsigned long load_elf_interp(str
 			 * <= p_memsize so it's only necessary to check p_memsz.
 			 */
 			k = load_addr + eppnt->p_vaddr;
-			if (k > TASK_SIZE ||
+			if (BAD_ADDR(k) ||
 			    eppnt->p_filesz > eppnt->p_memsz ||
 			    eppnt->p_memsz > TASK_SIZE ||
 			    TASK_SIZE - eppnt->p_memsz < k) {
@@ -888,7 +888,7 @@ static int load_elf_binary(struct linux_
 		 * allowed task size. Note that p_filesz must always be
 		 * <= p_memsz so it is only necessary to check p_memsz.
 		 */
-		if (k > TASK_SIZE || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
+		if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
 		    elf_ppnt->p_memsz > TASK_SIZE ||
 		    TASK_SIZE - elf_ppnt->p_memsz < k) {
 			/* set_brk can never work. Avoid overflows. */
-- 
Chuck
 "You can't read a newspaper if you can't read."  --George W. Bush
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