lkml.org 
[lkml]   [2003]   [Feb]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] Prevent setting 32 uids/gids in the error range
Date
Tridge noticed that getegid() was returning EPERM.

I used -1000 since that's what PTR_ERR uses, but i386 _syscall macros
use -125: I don't suppose it really matters.

Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.

Name: User and Group ID range check patch
Author: Rusty Russell
Status: Tested on 2.5.61-bk1

D: sys_getuid etc return long, which means that setting your gid to -1
D: on 32-bit platforms causes sys_getuid to return "EPERM", for example.

diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.61-bk1/include/linux/types.h working-2.5.61-bk1-valid_ids/include/linux/types.h
--- linux-2.5.61-bk1/include/linux/types.h 2003-02-11 14:26:19.000000000 +1100
+++ working-2.5.61-bk1-valid_ids/include/linux/types.h 2003-02-17 17:26:38.000000000 +1100
@@ -34,6 +34,10 @@ typedef __kernel_gid32_t gid_t;
typedef __kernel_uid16_t uid16_t;
typedef __kernel_gid16_t gid16_t;

+/* If we allowed these to be set, getuid etc. would break (they return long) */
+#define is_valid_gid(gid) ((unsigned long)(gid) < -1000UL)
+#define is_valid_uid(uid) ((unsigned long)(uid) < -1000UL)
+
#ifdef CONFIG_UID16
/* This is defined by include/asm-{arch}/posix_types.h */
typedef __kernel_old_uid_t old_uid_t;
diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.61-bk1/kernel/sys.c working-2.5.61-bk1-valid_ids/kernel/sys.c
--- linux-2.5.61-bk1/kernel/sys.c 2003-02-17 11:37:55.000000000 +1100
+++ working-2.5.61-bk1-valid_ids/kernel/sys.c 2003-02-17 18:11:01.000000000 +1100
@@ -658,6 +658,9 @@ asmlinkage long sys_setuid(uid_t uid)
if (retval)
return retval;

+ if (!is_valid_uid(uid))
+ return -EINVAL;
+
old_ruid = new_ruid = current->uid;
old_suid = current->suid;
new_suid = old_suid;
@@ -700,6 +705,11 @@ asmlinkage long sys_setresuid(uid_t ruid
if (retval)
return retval;

+ if ((!is_valid_uid(ruid) && ruid != (uid_t)-1)
+ || (!is_valid_uid(euid) && euid != (uid_t)-1)
+ || (!is_valid_uid(suid) && suid != (uid_t)-1))
+ return -EINVAL;
+
if (!capable(CAP_SETUID)) {
if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
(ruid != current->euid) && (ruid != current->suid))
@@ -752,6 +762,11 @@ asmlinkage long sys_setresgid(gid_t rgid
if (retval)
return retval;

+ if ((!is_valid_gid(rgid) && rgid != (gid_t)-1)
+ || (!is_valid_gid(egid) && egid != (gid_t)-1)
+ || (!is_valid_gid(sgid) && sgid != (gid_t)-1))
+ return -EINVAL;
+
if (!capable(CAP_SETGID)) {
if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
(rgid != current->egid) && (rgid != current->sgid))
@@ -806,6 +821,9 @@ asmlinkage long sys_setfsuid(uid_t uid)
if (retval)
return retval;

+ if (!is_valid_uid(uid))
+ return -EINVAL;
+
old_fsuid = current->fsuid;
if (uid == current->uid || uid == current->euid ||
uid == current->suid || uid == current->fsuid ||
@@ -838,6 +856,9 @@ asmlinkage long sys_setfsgid(gid_t gid)
if (retval)
return retval;

+ if (!is_valid_gid(gid))
+ return -EINVAL;
+
old_fsgid = current->fsgid;
if (gid == current->gid || gid == current->egid ||
gid == current->sgid || gid == current->fsgid ||
@@ -1059,7 +1080,7 @@ asmlinkage long sys_getgroups(int gidset
asmlinkage long sys_setgroups(int gidsetsize, gid_t *grouplist)
{
gid_t groups[NGROUPS];
- int retval;
+ int retval, i;

if (!capable(CAP_SETGID))
return -EPERM;
@@ -1067,6 +1088,9 @@ asmlinkage long sys_setgroups(int gidset
return -EINVAL;
if(copy_from_user(groups, grouplist, gidsetsize * sizeof(gid_t)))
return -EFAULT;
+ for (i = 0; i < gidsetsize; i++)
+ if (!is_valid_gid(groups[i]))
+ return -EINVAL;
retval = security_task_setgroups(gidsetsize, groups);
if (retval)
return retval;
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2005-03-22 13:33    [W:0.037 / U:2.180 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site