mirror of https://github.com/torvalds/linux.git
d045c77c1a
On architectures where the stack grows upwards (CONFIG_STACK_GROWSUP=y, currently parisc and metag only) stack randomization sometimes leads to crashes when the stack ulimit is set to lower values than STACK_RND_MASK (which is 8 MB by default if not defined in arch-specific headers). The problem is, that when the stack vm_area_struct is set up in fs/exec.c, the additional space needed for the stack randomization (as defined by the value of STACK_RND_MASK) was not taken into account yet and as such, when the stack randomization code added a random offset to the stack start, the stack effectively got smaller than what the user defined via rlimit_max(RLIMIT_STACK) which then sometimes leads to out-of-stack situations and crashes. This patch fixes it by adding the maximum possible amount of memory (based on STACK_RND_MASK) which theoretically could be added by the stack randomization code to the initial stack size. That way, the user-defined stack size is always guaranteed to be at minimum what is defined via rlimit_max(RLIMIT_STACK). This bug is currently not visible on the metag architecture, because on metag STACK_RND_MASK is defined to 0 which effectively disables stack randomization. The changes to fs/exec.c are inside an "#ifdef CONFIG_STACK_GROWSUP" section, so it does not affect other platformws beside those where the stack grows upwards (parisc and metag). Signed-off-by: Helge Deller <deller@gmx.de> Cc: linux-parisc@vger.kernel.org Cc: James Hogan <james.hogan@imgtec.com> Cc: linux-metag@vger.kernel.org Cc: stable@vger.kernel.org # v3.16+ |
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| .. | ||
| .gitignore | ||
| Makefile | ||
| asm-offsets.c | ||
| audit.c | ||
| binfmt_elf32.c | ||
| cache.c | ||
| compat_audit.c | ||
| drivers.c | ||
| entry.S | ||
| firmware.c | ||
| ftrace.c | ||
| hardware.c | ||
| head.S | ||
| hpmc.S | ||
| inventory.c | ||
| irq.c | ||
| module.c | ||
| pa7300lc.c | ||
| pacache.S | ||
| parisc_ksyms.c | ||
| pci-dma.c | ||
| pci.c | ||
| pdc_chassis.c | ||
| pdc_cons.c | ||
| perf.c | ||
| perf_asm.S | ||
| perf_images.h | ||
| process.c | ||
| processor.c | ||
| ptrace.c | ||
| real2.S | ||
| setup.c | ||
| signal.c | ||
| signal32.c | ||
| signal32.h | ||
| smp.c | ||
| stacktrace.c | ||
| sys_parisc.c | ||
| sys_parisc32.c | ||
| syscall.S | ||
| syscall_table.S | ||
| time.c | ||
| topology.c | ||
| traps.c | ||
| unaligned.c | ||
| unwind.c | ||
| vmlinux.lds.S | ||