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authorStephen Smalley <sds@tycho.nsa.gov>2006-02-01 06:05:54 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-01 11:53:18 -0500
commitdb4c9641def55d36a6f9df79deb8a949292313ca (patch)
treef3b786a346f0c987d796784e1e08154338263ad3 /security
parentee13d785eac1fbe7e79ecca77bf7e902734a0b30 (diff)
[PATCH] selinux: fix and cleanup mprotect checks
Fix the SELinux mprotect checks on executable mappings so that they are not re-applied when the mapping is already executable as well as cleaning up the code. This avoids a situation where e.g. an application is prevented from removing PROT_WRITE on an already executable mapping previously authorized via execmem permission due to an execmod denial. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'security')
-rw-r--r--security/selinux/hooks.c50
1 files changed, 21 insertions, 29 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index b9f8d9731c3d..1bb5eea3b8c1 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2454,35 +2454,27 @@ static int selinux_file_mprotect(struct vm_area_struct *vma,
2454 prot = reqprot; 2454 prot = reqprot;
2455 2455
2456#ifndef CONFIG_PPC32 2456#ifndef CONFIG_PPC32
2457 if ((prot & PROT_EXEC) && !(vma->vm_flags & VM_EXECUTABLE) && 2457 if ((prot & PROT_EXEC) && !(vma->vm_flags & VM_EXEC)) {
2458 (vma->vm_start >= vma->vm_mm->start_brk && 2458 rc = 0;
2459 vma->vm_end <= vma->vm_mm->brk)) { 2459 if (vma->vm_start >= vma->vm_mm->start_brk &&
2460 /* 2460 vma->vm_end <= vma->vm_mm->brk) {
2461 * We are making an executable mapping in the brk region. 2461 rc = task_has_perm(current, current,
2462 * This has an additional execheap check. 2462 PROCESS__EXECHEAP);
2463 */ 2463 } else if (!vma->vm_file &&
2464 rc = task_has_perm(current, current, PROCESS__EXECHEAP); 2464 vma->vm_start <= vma->vm_mm->start_stack &&
2465 if (rc) 2465 vma->vm_end >= vma->vm_mm->start_stack) {
2466 return rc; 2466 rc = task_has_perm(current, current, PROCESS__EXECSTACK);
2467 } 2467 } else if (vma->vm_file && vma->anon_vma) {
2468 if (vma->vm_file != NULL && vma->anon_vma != NULL && (prot & PROT_EXEC)) { 2468 /*
2469 /* 2469 * We are making executable a file mapping that has
2470 * We are making executable a file mapping that has 2470 * had some COW done. Since pages might have been
2471 * had some COW done. Since pages might have been written, 2471 * written, check ability to execute the possibly
2472 * check ability to execute the possibly modified content. 2472 * modified content. This typically should only
2473 * This typically should only occur for text relocations. 2473 * occur for text relocations.
2474 */ 2474 */
2475 int rc = file_has_perm(current, vma->vm_file, FILE__EXECMOD); 2475 rc = file_has_perm(current, vma->vm_file,
2476 if (rc) 2476 FILE__EXECMOD);
2477 return rc; 2477 }
2478 }
2479 if (!vma->vm_file && (prot & PROT_EXEC) &&
2480 vma->vm_start <= vma->vm_mm->start_stack &&
2481 vma->vm_end >= vma->vm_mm->start_stack) {
2482 /* Attempt to make the process stack executable.
2483 * This has an additional execstack check.
2484 */
2485 rc = task_has_perm(current, current, PROCESS__EXECSTACK);
2486 if (rc) 2478 if (rc)
2487 return rc; 2479 return rc;
2488 } 2480 }