CVE - CVE-2024-26706

CVE-ID
CVE-2024-26706	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
In the Linux kernel, the following vulnerability has been resolved: parisc: Fix random data corruption from exception handler The current exception handler implementation, which assists when accessing user space memory, may exhibit random data corruption if the compiler decides to use a different register than the specified register %r29 (defined in ASM_EXCEPTIONTABLE_REG) for the error code. If the compiler choose another register, the fault handler will nevertheless store -EFAULT into %r29 and thus trash whatever this register is used for. Looking at the assembly I found that this happens sometimes in emulate_ldd(). To solve the issue, the easiest solution would be if it somehow is possible to tell the fault handler which register is used to hold the error code. Using %0 or %1 in the inline assembly is not posssible as it will show up as e.g. %r29 (with the "%r" prefix), which the GNU assembler can not convert to an integer. This patch takes another, better and more flexible approach: We extend the __ex_table (which is out of the execution path) by one 32-word. In this word we tell the compiler to insert the assembler instruction "or %r0,%r0,%reg", where %reg references the register which the compiler choosed for the error return code. In case of an access failure, the fault handler finds the __ex_table entry and can examine the opcode. The used register is encoded in the lowest 5 bits, and the fault handler can then store -EFAULT into this register. Since we extend the __ex_table to 3 words we can't use the BUILDTIME_TABLE_SORT config option any longer.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/23027309b099ffc4efca5477009a11dccbdae592 URL:https://git.kernel.org/stable/c/23027309b099ffc4efca5477009a11dccbdae592 MISC:https://git.kernel.org/stable/c/8b1d72395635af45410b66cc4c4ab37a12c4a831 URL:https://git.kernel.org/stable/c/8b1d72395635af45410b66cc4c4ab37a12c4a831 MISC:https://git.kernel.org/stable/c/ce31d79aa1f13a2345791f84935281a2c194e003 URL:https://git.kernel.org/stable/c/ce31d79aa1f13a2345791f84935281a2c194e003 MISC:https://git.kernel.org/stable/c/fa69a8063f8b27f3c7434a0d4f464a76a62f24d2 URL:https://git.kernel.org/stable/c/fa69a8063f8b27f3c7434a0d4f464a76a62f24d2
Assigning CNA
kernel.org
Date Record Created
20240219	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20240219)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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