From: Arnd Bergmann <[email protected]> The compat version of sys_kexec_load() uses compat_alloc_user_space to convert the user-provided arguments into the native format.
Move the conversion into the regular implementation with an in_compat_syscall() check to simplify it and avoid the compat_alloc_user_space() call. compat_sys_kexec_load() now behaves the same as sys_kexec_load(). Signed-off-by: Arnd Bergmann <[email protected]> --- include/linux/kexec.h | 2 - kernel/kexec.c | 95 +++++++++++++++++++------------------------ 2 files changed, 42 insertions(+), 55 deletions(-) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index 9e93bef52968..7b6717cd5c4a 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -88,14 +88,12 @@ struct kexec_segment { size_t memsz; }; -#ifdef CONFIG_COMPAT struct compat_kexec_segment { compat_uptr_t buf; compat_size_t bufsz; compat_ulong_t mem; /* User space sees this as a (void *) ... */ compat_size_t memsz; }; -#endif #ifdef CONFIG_KEXEC_FILE struct purgatory_info { diff --git a/kernel/kexec.c b/kernel/kexec.c index c82c6c06f051..ec04791eea3e 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -19,21 +19,46 @@ #include "kexec_internal.h" +static int copy_user_compat_segment_list(struct kimage *image, + unsigned long nr_segments, + void __user *segments) +{ + struct compat_kexec_segment __user *cs = segments; + struct compat_kexec_segment segment; + int i; + + for (i=0; i < nr_segments; i++) { + if (copy_from_user(&segment, &cs[i], sizeof(segment))) + return -EFAULT; + + image->segment[i] = (struct kexec_segment) { + .buf = compat_ptr(segment.buf), + .bufsz = segment.bufsz, + .mem = segment.mem, + .memsz = segment.memsz, + }; + } + + return 0; +} + + static int copy_user_segment_list(struct kimage *image, unsigned long nr_segments, struct kexec_segment __user *segments) { - int ret; size_t segment_bytes; /* Read in the segments */ image->nr_segments = nr_segments; segment_bytes = nr_segments * sizeof(*segments); - ret = copy_from_user(image->segment, segments, segment_bytes); - if (ret) - ret = -EFAULT; + if (in_compat_syscall()) + return copy_user_compat_segment_list(image, nr_segments, segments); - return ret; + if (copy_from_user(image->segment, segments, segment_bytes)) + return -EFAULT; + + return 0; } static int kimage_alloc_init(struct kimage **rimage, unsigned long entry, @@ -233,8 +258,9 @@ static inline int kexec_load_check(unsigned long nr_segments, return 0; } -SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments, - struct kexec_segment __user *, segments, unsigned long, flags) +static int kernel_kexec_load(unsigned long entry, unsigned long nr_segments, + struct kexec_segment __user * segments, + unsigned long flags) { int result; @@ -265,57 +291,20 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments, return result; } +SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments, + struct kexec_segment __user *, segments, unsigned long, flags) +{ + return kernel_kexec_load(entry, nr_segments, segments, flags); +} + #ifdef CONFIG_COMPAT COMPAT_SYSCALL_DEFINE4(kexec_load, compat_ulong_t, entry, compat_ulong_t, nr_segments, struct compat_kexec_segment __user *, segments, compat_ulong_t, flags) { - struct compat_kexec_segment in; - struct kexec_segment out, __user *ksegments; - unsigned long i, result; - - result = kexec_load_check(nr_segments, flags); - if (result) - return result; - - /* Don't allow clients that don't understand the native - * architecture to do anything. - */ - if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT) - return -EINVAL; - - ksegments = compat_alloc_user_space(nr_segments * sizeof(out)); - for (i = 0; i < nr_segments; i++) { - result = copy_from_user(&in, &segments[i], sizeof(in)); - if (result) - return -EFAULT; - - out.buf = compat_ptr(in.buf); - out.bufsz = in.bufsz; - out.mem = in.mem; - out.memsz = in.memsz; - - result = copy_to_user(&ksegments[i], &out, sizeof(out)); - if (result) - return -EFAULT; - } - - /* Because we write directly to the reserved memory - * region when loading crash kernels we need a mutex here to - * prevent multiple crash kernels from attempting to load - * simultaneously, and to prevent a crash kernel from loading - * over the top of a in use crash kernel. - * - * KISS: always take the mutex. - */ - if (!mutex_trylock(&kexec_mutex)) - return -EBUSY; - - result = do_kexec_load(entry, nr_segments, ksegments, flags); - - mutex_unlock(&kexec_mutex); - - return result; + return kernel_kexec_load(entry, nr_segments, + (struct kexec_segment __user *)segments, + flags); } #endif -- 2.27.0 _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
