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authorVasant Hegde <hegdevasant@linux.vnet.ibm.com>2015-10-16 15:53:29 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2015-10-22 11:03:25 +1100
commit8832317f662c06f5c06e638f57bfe89a71c9b266 (patch)
tree31aa6635b4bdcae31e2af6566f58634d1b7fe50c /arch
parent53c656c4138511c2ba54df413dc29976cfa9f084 (diff)
powerpc/rtas: Validate rtas.entry before calling enter_rtas()
Currently we do not validate rtas.entry before calling enter_rtas(). This leads to a kernel oops when user space calls rtas system call on a powernv platform (see below). This patch adds code to validate rtas.entry before making enter_rtas() call. Oops: Exception in kernel mode, sig: 4 [#1] SMP NR_CPUS=1024 NUMA PowerNV task: c000000004294b80 ti: c0000007e1a78000 task.ti: c0000007e1a78000 NIP: 0000000000000000 LR: 0000000000009c14 CTR: c000000000423140 REGS: c0000007e1a7b920 TRAP: 0e40 Not tainted (3.18.17-340.el7_1.pkvm3_1_0.2400.1.ppc64le) MSR: 1000000000081000 <HV,ME> CR: 00000000 XER: 00000000 CFAR: c000000000009c0c SOFTE: 0 NIP [0000000000000000] (null) LR [0000000000009c14] 0x9c14 Call Trace: [c0000007e1a7bba0] [c00000000041a7f4] avc_has_perm_noaudit+0x54/0x110 (unreliable) [c0000007e1a7bd80] [c00000000002ddc0] ppc_rtas+0x150/0x2d0 [c0000007e1a7be30] [c000000000009358] syscall_exit+0x0/0x98 Cc: stable@vger.kernel.org # v3.2+ Fixes: 55190f88789a ("powerpc: Add skeleton PowerNV platform") Reported-by: NAGESWARA R. SASTRY <nasastry@in.ibm.com> Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com> [mpe: Reword change log, trim oops, and add stable + fixes] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kernel/rtas.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 84bf934cf748..5a753fae8265 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -1043,6 +1043,9 @@ asmlinkage int ppc_rtas(struct rtas_args __user *uargs)
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
+ if (!rtas.entry)
+ return -EINVAL;
+
if (copy_from_user(&args, uargs, 3 * sizeof(u32)) != 0)
return -EFAULT;