From: Zheyu Ma zheyuma97@gmail.com
stable inclusion from stable-v4.19.238 commit 1aea36a62f0a0ad67eccc945bac0bd6422ef720f category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5GKWU CVE: CVE-2022-2380
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When the sm712fb driver writes three bytes to the framebuffer, the driver will crash:
BUG: unable to handle page fault for address: ffffc90001ffffff RIP: 0010:smtcfb_write+0x454/0x5b0 Call Trace: vfs_write+0x291/0xd60 ? do_sys_openat2+0x27d/0x350 ? __fget_light+0x54/0x340 ksys_write+0xce/0x190 do_syscall_64+0x43/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae
Fix it by removing the open-coded endianness fixup-code.
Signed-off-by: Zheyu Ma zheyuma97@gmail.com Signed-off-by: Helge Deller deller@gmx.de Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Xia Longlong xialonglong1@huawei.com Reviewed-by: Xiu Jianfeng xiujianfeng@huawei.com Reviewed-by: Kefeng Wang wangkefeng.wang@huawei.com Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- drivers/video/fbdev/sm712fb.c | 21 ++++----------------- 1 file changed, 4 insertions(+), 17 deletions(-)
diff --git a/drivers/video/fbdev/sm712fb.c b/drivers/video/fbdev/sm712fb.c index 0713b8444ecc..5da4c287d393 100644 --- a/drivers/video/fbdev/sm712fb.c +++ b/drivers/video/fbdev/sm712fb.c @@ -1119,7 +1119,7 @@ static ssize_t smtcfb_write(struct fb_info *info, const char __user *buf, count = total_size - p; }
- buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count, GFP_KERNEL); + buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!buffer) return -ENOMEM;
@@ -1137,24 +1137,11 @@ static ssize_t smtcfb_write(struct fb_info *info, const char __user *buf, break; }
- for (i = c >> 2; i--;) { - fb_writel(big_swap(*src), dst++); + for (i = (c + 3) >> 2; i--;) { + fb_writel(big_swap(*src), dst); + dst++; src++; } - if (c & 3) { - u8 *src8 = (u8 *)src; - u8 __iomem *dst8 = (u8 __iomem *)dst; - - for (i = c & 3; i--;) { - if (i & 1) { - fb_writeb(*src8++, ++dst8); - } else { - fb_writeb(*src8++, --dst8); - dst8 += 2; - } - } - dst = (u32 __iomem *)dst8; - }
*ppos += c; buf += c;