diff options
Diffstat (limited to 'arch/x86/kernel/dumpstack.c')
| -rw-r--r-- | arch/x86/kernel/dumpstack.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index 1596e6bfea6f..f56895106ccf 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -90,14 +90,24 @@ static void printk_stack_address(unsigned long address, int reliable, * Thus, the 2/3rds prologue and 64 byte OPCODE_BUFSIZE is just a random * guesstimate in attempt to achieve all of the above. */ -void show_opcodes(u8 *rip, const char *loglvl) +void show_opcodes(struct pt_regs *regs, const char *loglvl) { #define PROLOGUE_SIZE 42 #define EPILOGUE_SIZE 21 #define OPCODE_BUFSIZE (PROLOGUE_SIZE + 1 + EPILOGUE_SIZE) u8 opcodes[OPCODE_BUFSIZE]; + unsigned long prologue = regs->ip - PROLOGUE_SIZE; + bool bad_ip; - if (probe_kernel_read(opcodes, rip - PROLOGUE_SIZE, OPCODE_BUFSIZE)) { + /* + * Make sure userspace isn't trying to trick us into dumping kernel + * memory by pointing the userspace instruction pointer at it. + */ + bad_ip = user_mode(regs) && + __chk_range_not_ok(prologue, OPCODE_BUFSIZE, TASK_SIZE_MAX); + + if (bad_ip || probe_kernel_read(opcodes, (u8 *)prologue, + OPCODE_BUFSIZE)) { printk("%sCode: Bad RIP value.\n", loglvl); } else { printk("%sCode: %" __stringify(PROLOGUE_SIZE) "ph <%02x> %" @@ -113,7 +123,7 @@ void show_ip(struct pt_regs *regs, const char *loglvl) #else printk("%sRIP: %04x:%pS\n", loglvl, (int)regs->cs, (void *)regs->ip); #endif - show_opcodes((u8 *)regs->ip, loglvl); + show_opcodes(regs, loglvl); } void show_iret_regs(struct pt_regs *regs) |