diff options
| author | Jia Zhang <zhang.jia@linux.alibaba.com> | 2018-02-12 22:44:53 +0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-02-13 09:15:58 +0100 |
| commit | 595dd46ebfc10be041a365d0a3fa99df50b6ba73 (patch) | |
| tree | 3e781a635cad1504225e1753289d7ffecb1d8a6f | |
| parent | aec6487e994d2f625197970a56a4aac40c2c7547 (diff) | |
vfs/proc/kcore, x86/mm/kcore: Fix SMAP fault when dumping vsyscall user page
Commit:
df04abfd181a ("fs/proc/kcore.c: Add bounce buffer for ktext data")
... introduced a bounce buffer to work around CONFIG_HARDENED_USERCOPY=y.
However, accessing the vsyscall user page will cause an SMAP fault.
Replace memcpy() with copy_from_user() to fix this bug works, but adding
a common way to handle this sort of user page may be useful for future.
Currently, only vsyscall page requires KCORE_USER.
Signed-off-by: Jia Zhang <zhang.jia@linux.alibaba.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: jolsa@redhat.com
Link: http://lkml.kernel.org/r/1518446694-21124-2-git-send-email-zhang.jia@linux.alibaba.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/mm/init_64.c | 3 | ||||
| -rw-r--r-- | fs/proc/kcore.c | 4 | ||||
| -rw-r--r-- | include/linux/kcore.h | 1 |
3 files changed, 6 insertions, 2 deletions
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 1ab42c852069..6aa33d1e198f 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1193,8 +1193,7 @@ void __init mem_init(void) register_page_bootmem_info(); /* Register memory areas for /proc/kcore */ - kclist_add(&kcore_vsyscall, (void *)VSYSCALL_ADDR, - PAGE_SIZE, KCORE_OTHER); + kclist_add(&kcore_vsyscall, (void *)VSYSCALL_ADDR, PAGE_SIZE, KCORE_USER); mem_init_print_info(NULL); } diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c index e8a93bc8285d..d1e82761de81 100644 --- a/fs/proc/kcore.c +++ b/fs/proc/kcore.c @@ -510,6 +510,10 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) /* we have to zero-fill user buffer even if no read */ if (copy_to_user(buffer, buf, tsz)) return -EFAULT; + } else if (m->type == KCORE_USER) { + /* User page is handled prior to normal kernel page: */ + if (copy_to_user(buffer, (char *)start, tsz)) + return -EFAULT; } else { if (kern_addr_valid(start)) { /* diff --git a/include/linux/kcore.h b/include/linux/kcore.h index 7ff25a808fef..80db19d3a505 100644 --- a/include/linux/kcore.h +++ b/include/linux/kcore.h @@ -10,6 +10,7 @@ enum kcore_type { KCORE_VMALLOC, KCORE_RAM, KCORE_VMEMMAP, + KCORE_USER, KCORE_OTHER, }; |