/* * Access kernel memory without faulting. */ #include #include #include /** * probe_kernel_read(): safely attempt to read from a location * @dst: pointer to the buffer that shall take the data * @src: address to read from * @size: size of the data chunk * * Safely read from address @src to the buffer at @dst. If a kernel fault * happens, handle that and return -EFAULT. * * We ensure that the copy_from_user is executed in atomic context so that * do_page_fault() doesn't attempt to take mmap_sem. This makes * probe_kernel_read() suitable for use within regions where the caller * already holds mmap_sem, or other locks which nest inside mmap_sem. */ long __weak probe_kernel_read(void *dst, const void *src, size_t size) __attribute__((alias("__probe_kernel_read"))); long __probe_kernel_read(void *dst, const void *src, size_t size) { long ret; mm_segment_t old_fs = get_fs(); set_fs(KERNEL_DS); pagefault_disable(); ret = __copy_from_user_inatomic(dst, (__force const void __user *)src, size); pagefault_enable(); set_fs(old_fs); return ret ? -EFAULT : 0; } EXPORT_SYMBOL_GPL(probe_kernel_read); /** * probe_kernel_write(): safely attempt to write to a location * @dst: address to write to * @src: pointer to the data that shall be written * @size: size of the data chunk * * Safely write to address @dst from the buffer at @src. If a kernel fault * happens, handle that and return -EFAULT. */ long __weak probe_kernel_write(void *dst, const void *src, size_t size) __attribute__((alias("__probe_kernel_write"))); long __probe_kernel_write(void *dst, const void *src, size_t size) { long ret; mm_segment_t old_fs = get_fs(); set_fs(KERNEL_DS); pagefault_disable(); ret = __copy_to_user_inatomic((__force void __user *)dst, src, size); pagefault_enable(); set_fs(old_fs); return ret ? -EFAULT : 0; } EXPORT_SYMBOL_GPL(probe_kernel_write); /** * strncpy_from_unsafe: - Copy a NUL terminated string from unsafe address. * @dst: Destination address, in kernel space. This buffer must be at * least @count bytes long. * @src: Unsafe address. * @count: Maximum number of bytes to copy, including the trailing NUL. * * Copies a NUL-terminated string from unsafe address to kernel buffer. * * On success, returns the length of the string INCLUDING the trailing NUL. * * If access fails, returns -EFAULT (some data may have been copied * and the trailing NUL added). * * If @count is smaller than the length of the string, copies @count-1 bytes, * sets the last byte of @dst buffer to NUL and returns @count. */ long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count) { mm_segment_t old_fs = get_fs(); const void *src = unsafe_addr; long ret; if (unlikely(count <= 0)) return 0; set_fs(KERNEL_DS); pagefault_disable(); do { ret = __get_user(*dst++, (const char __user __force *)src++); } while (dst[-1] && ret == 0 && src - unsafe_addr < count); dst[-1] = '\0'; pagefault_enable(); set_fs(old_fs); return ret ? -EFAULT : src - unsafe_addr; } &id=b5b46c4740aed1538544f0fa849c5b76c7823469'>8021q
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authorJiri Slaby <jslaby@suse.cz>2017-01-18 14:29:21 +0100
committerIngo Molnar <mingo@kernel.org>2017-01-19 08:39:44 +0100
commitb5b46c4740aed1538544f0fa849c5b76c7823469 (patch)
tree125e7aced4835bad6f6a0c0d02d012f333caf922 /net/8021q
parentfa19a769f82fb9a5ca000b83cacd13fcaeda51ac (diff)
objtool: Fix IRET's opcode
The IRET opcode is 0xcf according to the Intel manual and also to objdump of my vmlinux: 1ea8: 48 cf iretq Fix the opcode in arch_decode_instruction(). The previous value (0xc5) seems to correspond to LDS. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170118132921.19319-1-jslaby@suse.cz Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'net/8021q')