漏洞标题
powerpc/47x：修复47x系统调用返回时的崩溃。
漏洞描述信息
在Linux内核中，已经解决了以下漏洞：
powerpc/47x: 修复47x系统调用返回崩溃问题
Eddie报告说，在他的476 FSP2系统的最新内核启动时会崩溃。
NIP [b7ee2000] 地址为0xb7ee2000
LR [8c008000] 地址为0x8c008000
Call Trace 和 Instruction dump 信息显示了问题的具体位置。漏洞的根源在于commit 6f76a01（“powerpc/syscall: 实现系统调用入口/出口逻辑，C语言针对PPC32”）引入的一个意外改动，它不小心删除了"1"标签并在其他地方重用了它。
修复这个问题的方法是在正确的位置添加具有明确名称的局部标签。需要注意的是，返回标签需要在ifdef之外，以便于CONFIG_PPC_47x=n编译时不出现问题。
CVSS信息
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
漏洞类别
空指针解引用
漏洞标题
powerpc/47x: Fix 47x syscall return crash
漏洞描述信息
In the Linux kernel, the following vulnerability has been resolved:
powerpc/47x: Fix 47x syscall return crash
Eddie reported that newer kernels were crashing during boot on his 476
FSP2 system:
kernel tried to execute user page (b7ee2000) - exploit attempt? (uid: 0)
BUG: Unable to handle kernel instruction fetch
Faulting instruction address: 0xb7ee2000
Oops: Kernel access of bad area, sig: 11 [#1]
BE PAGE_SIZE=4K FSP-2
Modules linked in:
CPU: 0 PID: 61 Comm: mount Not tainted 6.1.55-d23900f.ppcnf-fsp2 #1
Hardware name: ibm,fsp2 476fpe 0x7ff520c0 FSP-2
NIP: b7ee2000 LR: 8c008000 CTR: 00000000
REGS: bffebd83 TRAP: 0400 Not tainted (6.1.55-d23900f.ppcnf-fs p2)
MSR: 00000030 <IR,DR> CR: 00001000 XER: 20000000
GPR00: c00110ac bffebe63 bffebe7e bffebe88 8c008000 00001000 00000d12 b7ee2000
GPR08: 00000033 00000000 00000000 c139df10 48224824 1016c314 10160000 00000000
GPR16: 10160000 10160000 00000008 00000000 10160000 00000000 10160000 1017f5b0
GPR24: 1017fa50 1017f4f0 1017fa50 1017f740 1017f630 00000000 00000000 1017f4f0
NIP [b7ee2000] 0xb7ee2000
LR [8c008000] 0x8c008000
Call Trace:
Instruction dump:
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
---[ end trace 0000000000000000 ]---
The problem is in ret_from_syscall where the check for
icache_44x_need_flush is done. When the flush is needed the code jumps
out-of-line to do the flush, and then intends to jump back to continue
the syscall return.
However the branch back to label 1b doesn't return to the correct
location, instead branching back just prior to the return to userspace,
causing bogus register values to be used by the rfi.
The breakage was introduced by commit 6f76a01173cc
("powerpc/syscall: implement system call entry/exit logic in C for PPC32") which
inadvertently removed the "1" label and reused it elsewhere.
Fix it by adding named local labels in the correct locations. Note that
the return label needs to be outside the ifdef so that CONFIG_PPC_47x=n
compiles.
CVSS信息
N/A
漏洞类别
N/A
漏洞标题
Linux kernel 安全漏洞
漏洞描述信息
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于无法处理内核指令。
CVSS信息
N/A
漏洞类别
其他