Messages in this thread Patch in this message | | | Date | Fri, 31 Aug 2018 15:51:52 +0200 | Subject | [PATCH v2] x86/dumpstack: fix address space casting in show_opcodes() | From | Jann Horn <> |
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I sloppily passed a kernel-typed pointer to __range_not_ok(), and sparse doesn't like that. Make `prologue` an unsigned long and cast it to a kernel pointer when calling probe_kernel_read(), just like ~everyone else who calls probe_kernel_read(). Instead of __range_not_ok() with a cast, call __chk_range_not_ok directly.
Fixes: a644cf538b11 ("x86/dumpstack: Don't dump kernel memory based on usermode RIP") Signed-off-by: Jann Horn <jannh@google.com> --- arch/x86/kernel/dumpstack.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index 605c60b1624f..f56895106ccf 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -96,7 +96,7 @@ void show_opcodes(struct pt_regs *regs, const char *loglvl) #define EPILOGUE_SIZE 21 #define OPCODE_BUFSIZE (PROLOGUE_SIZE + 1 + EPILOGUE_SIZE) u8 opcodes[OPCODE_BUFSIZE]; - u8 *prologue = (u8 *)(regs->ip - PROLOGUE_SIZE); + unsigned long prologue = regs->ip - PROLOGUE_SIZE; bool bad_ip; /* @@ -104,9 +104,10 @@ void show_opcodes(struct pt_regs *regs, const char *loglvl) * memory by pointing the userspace instruction pointer at it. */ bad_ip = user_mode(regs) && - __range_not_ok(prologue, OPCODE_BUFSIZE, TASK_SIZE_MAX); + __chk_range_not_ok(prologue, OPCODE_BUFSIZE, TASK_SIZE_MAX); - if (bad_ip || probe_kernel_read(opcodes, prologue, OPCODE_BUFSIZE)) { + 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> %" -- 2.19.0.rc1.350.ge57e33dbd1-goog
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