Messages in this thread Patch in this message | | | Date | Tue, 19 Dec 2017 13:52:23 -0800 | From | Kees Cook <> | Subject | [PATCH] Do not hash userspace addresses in fault handlers |
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The hashing of %p was designed to restrict kernel addresses. There is no reason to hash the userspace values seen during a segfault report, so switch these to %px. (Some architectures already use %lx.)
Fixes: ad67b74d2469d9b8 ("printk: hash addresses printed with %p") Signed-off-by: Kees Cook <keescook@chromium.org> --- Alternatively, we could enhance the %p hashing to only hash for values above TASK_SIZE, which would mean userspace values would automatically go unhashed... But that seems fragile to me. --- arch/sparc/mm/fault_32.c | 2 +- arch/sparc/mm/fault_64.c | 2 +- arch/um/kernel/trap.c | 2 +- arch/x86/mm/fault.c | 2 +- 4 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c index be3136f142a9..b969db2fde5f 100644 --- a/arch/sparc/mm/fault_32.c +++ b/arch/sparc/mm/fault_32.c @@ -113,7 +113,7 @@ show_signal_msg(struct pt_regs *regs, int sig, int code, if (!printk_ratelimit()) return; - printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x", + printk("%s%s[%d]: segfault at %lx ip %px (rpc %px) sp %px error %x", task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, tsk->comm, task_pid_nr(tsk), address, (void *)regs->pc, (void *)regs->u_regs[UREG_I7], diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c index 815c03d7a765..5c70edd7c56c 100644 --- a/arch/sparc/mm/fault_64.c +++ b/arch/sparc/mm/fault_64.c @@ -154,7 +154,7 @@ show_signal_msg(struct pt_regs *regs, int sig, int code, if (!printk_ratelimit()) return; - printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x", + printk("%s%s[%d]: segfault at %lx ip %px (rpc %px) sp %px error %x", task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, tsk->comm, task_pid_nr(tsk), address, (void *)regs->tpc, (void *)regs->u_regs[UREG_I7], diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c index 4e6fcb32620f..428644175956 100644 --- a/arch/um/kernel/trap.c +++ b/arch/um/kernel/trap.c @@ -150,7 +150,7 @@ static void show_segv_info(struct uml_pt_regs *regs) if (!printk_ratelimit()) return; - printk("%s%s[%d]: segfault at %lx ip %p sp %p error %x", + printk("%s%s[%d]: segfault at %lx ip %px sp %px error %x", task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, tsk->comm, task_pid_nr(tsk), FAULT_ADDRESS(*fi), (void *)UPT_IP(regs), (void *)UPT_SP(regs), diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index febf6980e653..06fe3d51d385 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -860,7 +860,7 @@ show_signal_msg(struct pt_regs *regs, unsigned long error_code, if (!printk_ratelimit()) return; - printk("%s%s[%d]: segfault at %lx ip %p sp %p error %lx", + printk("%s%s[%d]: segfault at %lx ip %px sp %px error %lx", task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, tsk->comm, task_pid_nr(tsk), address, (void *)regs->ip, (void *)regs->sp, error_code); -- 2.7.4
-- Kees Cook Pixel Security
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