In the Linux kernel, the following vulnerability has been resolved:
powerpc64/ftrace: fix module loading without patchable function entries
get_stubs_size assumes that there must always be at least one patchable function entry, which is not always the case (modules that export data but no code), otherwise it returns -ENOEXEC and thus the section header sh_size is set to that value. During module_memory_alloc() the size is passed to execmem_alloc() after being page-aligned and thus set to zero which will cause it to fail the allocation (and thus module loading) as __vmalloc_node_range() checks for zero-sized allocs and returns null:
[ 115.466896] module_64: cast_common: doesn't contain __patchable_function_entries. [ 115.469189] ------------[ cut here ]------------ [ 115.469496] WARNING: CPU: 0 PID: 274 at mm/vmalloc.c:3778 __vmalloc_node_range_noprof+0x8b4/0x8f0 ... [ 115.478574] ---[ end trace 0000000000000000 ]--- [ 115.479545] execmem: unable to allocate memory
Fix this by removing the check completely, since it is anyway not helpful to propagate this as an error upwards.
Exploitability
AV:LAC:LPR:LUI:NScope
S:UImpact
C:NI:NA:H5.5/CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H