Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
x86/MCE/AMD: Use an u64 for bank_map
Thee maximum number of MCA banks is 64 (MAX_NR_BANKS), see
a0bc32b3cacf (“x86/mce: Increase maximum number of banks to 64”).
However, the bank_map which contains a bitfield of which banks to initialize is of type unsigned int and that overflows when those bit numbers are >= 32, leading to UBSAN complaining correctly:
UBSAN: shift-out-of-bounds in arch/x86/kernel/cpu/mce/amd.c:1365:38 shift exponent 32 is too large for 32-bit type ‘int’
Change the bank_map to a u64 and use the proper BIT_ULL() macro when modifying bits in there.
[ bp: Rewrite commit message. ]
Details
- Affected product:
- AlmaLinux 9.2 ESU , TuxCare 9.6 ESU
- Affected packages:
- kernel @ 5.14.0 (+1 more)
In the Linux kernel, the following vulnerability has been resolved:
x86/MCE/AMD: Use an u64 for bank_map
Thee maximum number of MCA banks is 64 (MAX_NR_BANKS), see
a0bc32b3cacf (“x86/mce: Increase maximum number of banks to 64”).
However, the bank_map which contains a bitfield of which banks to initialize is of type unsigned int and that overflows when those bit numbers are >= 32, leading to UBSAN complaining correctly:
UBSAN: shift-out-of-bounds in arch/x86/kernel/cpu/mce/amd.c:1365:38 shift exponent 32 is too large for 32-bit type ‘int’
Change the bank_map to a u64 and use the proper BIT_ULL() macro when modifying bits in there.
[ bp: Rewrite commit message. ]