ich777/linux_media
1
0
Fork 0
mirror of https://github.com/tbsdtv/linux_media.git synced 2025-07-24 05:01:03 +02:00
Code Issues Packages Projects Releases Wiki Activity

uaccess: Add non-pagefault user-space write function

Browse Source 
Commit 3d7081822f ("uaccess: Add non-pagefault user-space read functions")
missed to add probe write function, therefore factor out a probe_write_common()
helper with most logic of probe_kernel_write() except setting KERNEL_DS, and
add a new probe_user_write() helper so it can be used from BPF side.

Again, on some archs, the user address space and kernel address space can
co-exist and be overlapping, so in such case, setting KERNEL_DS would mean
that the given address is treated as being in kernel address space.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/bpf/9df2542e68141bfa3addde631441ee45503856a8.1572649915.git.daniel@iogearbox.net
This commit is contained in:
Daniel Borkmann
2019-11-02 00:17:56 +01:00
committed by Alexei Starovoitov
parent e1cb7d2d60
commit 1d1585ca0f
2 changed files with 53 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
include/linux/uaccess.h
View File

@@ -337,6 +337,18 @@ extern long __probe_user_read(void *dst, const void __user *src, size_t size);
extern long notrace probe_kernel_write(void *dst, const void *src, size_t size);
extern long notrace __probe_kernel_write(void *dst, const void *src, size_t size);
/*
* probe_user_write(): safely attempt to write to a location in user space
* @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.
*/
extern long notrace probe_user_write(void __user *dst, const void *src, size_t size);
extern long notrace __probe_user_write(void __user *dst, const void *src, size_t size);
extern long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count);
extern long strncpy_from_unsafe_user(char *dst, const void __user *unsafe_addr,
long count);