diff options
author | Vaibhav Jain <vaibhav@linux.vnet.ibm.com> | 2017-11-28 08:23:04 +0530 |
---|---|---|
committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-11-29 19:36:13 +1100 |
commit | aca7573fde95152378361cba734996b384f3b1d3 (patch) | |
tree | 813e55743e0a1914448ba8e91f005f5224a21bc8 /arch/powerpc/kernel | |
parent | 2621e945fbf1d6df5f3f0ba7be5bae3d2cf9b6a5 (diff) |
powerpc: Avoid signed to unsigned conversion in set_thread_tidr()
There is an unsafe signed to unsigned conversion in set_thread_tidr()
that may cause an error value to be assigned to SPRN_TIDR register and
used as thread-id.
The issue happens as assign_thread_tidr() returns an int and
thread.tidr is an unsigned-long. So a negative error code returned
from assign_thread_tidr() will fail the error check and gets assigned
as tidr as a large positive value.
To fix this the patch assigns the return value of assign_thread_tidr()
to a temporary int and assigns it to thread.tidr iff its '> 0'.
The patch shouldn't impact the calling convention of set_thread_tidr()
i.e all -ve return-values are error codes and a return value of '0'
indicates success.
Fixes: ec233ede4c86("powerpc: Add support for setting SPRN_TIDR")
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Reviewed-by: Christophe Lombard clombard@linux.vnet.ibm.com
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel')
-rw-r--r-- | arch/powerpc/kernel/process.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index bfdd783e3916..d205b52e3850 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1569,16 +1569,19 @@ void arch_release_task_struct(struct task_struct *t) */ int set_thread_tidr(struct task_struct *t) { + int rc; + if (!cpu_has_feature(CPU_FTR_ARCH_300)) return -EINVAL; if (t != current) return -EINVAL; - t->thread.tidr = assign_thread_tidr(); - if (t->thread.tidr < 0) - return t->thread.tidr; + rc = assign_thread_tidr(); + if (rc < 0) + return rc; + t->thread.tidr = rc; mtspr(SPRN_TIDR, t->thread.tidr); return 0; |