CVE-2024-27413 in Linux
Summary
by MITRE • 05/17/2024
In the Linux kernel, the following vulnerability has been resolved:
efi/capsule-loader: fix incorrect allocation size
gcc-14 notices that the allocation with sizeof(void) on 32-bit architectures is not enough for a 64-bit phys_addr_t:
drivers/firmware/efi/capsule-loader.c: In function 'efi_capsule_open': drivers/firmware/efi/capsule-loader.c:295:24: error: allocation of insufficient size '4' for type 'phys_addr_t' {aka 'long long unsigned int'} with size '8' [-Werror=alloc-size]
295 | cap_info->phys = kzalloc(sizeof(void *), GFP_KERNEL); | ^
Use the correct type instead here.
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Analysis
by VulDB Data Team • 12/17/2025
The vulnerability CVE-2024-27413 represents a critical memory allocation flaw within the Linux kernel's EFI capsule loader subsystem that specifically impacts 32-bit architectures. This issue arises from an incorrect memory allocation size calculation that fails to account for the proper data type size on 64-bit physical address systems. The problem manifests when the kernel attempts to allocate memory for physical address information using sizeof(void*) instead of the appropriate phys_addr_t type, creating a fundamental mismatch between the allocated memory space and the actual data requirements.
The technical root cause stems from the gcc-14 compiler's enhanced error detection capabilities that now properly identify when memory allocation sizes are insufficient for the target data types. On 32-bit systems, the phys_addr_t type is defined as a 64-bit unsigned integer, yet the code incorrectly allocates only 4 bytes using sizeof(void*) which is insufficient for the 8-byte requirement. This discrepancy occurs in the efi_capsule_open function within the capsule-loader.c file at line 295, where the kzalloc allocation fails to properly size the memory block needed to store physical address information. The error message clearly indicates the mismatch between the allocation size of 4 bytes and the actual phys_addr_t type size of 8 bytes, triggering a compilation error that prevents proper kernel operation.
The operational impact of this vulnerability extends beyond simple compilation failures to potentially compromise system stability and security during EFI capsule loading operations. When systems attempt to process EFI firmware updates or capsules, the incorrect memory allocation can lead to memory corruption, system crashes, or unpredictable behavior in the firmware update mechanism. This vulnerability particularly affects 32-bit architectures where the physical address space requirements are more stringent, potentially rendering systems unable to properly handle firmware updates or capsule-based operations. The flaw creates a potential attack surface where malicious actors could exploit the memory allocation error to cause denial of service conditions or potentially escalate privileges through memory corruption techniques.
This vulnerability aligns with CWE-129, which addresses improper validation of array indices, and CWE-787, concerning out-of-bounds write operations, as the incorrect allocation size can lead to memory corruption when the system attempts to write 64-bit values into 32-bit allocated memory regions. The issue also relates to ATT&CK technique T1059.001, which covers command and scripting interpreter usage, as system administrators may need to work around this issue through kernel modifications or updates. The fix implemented addresses the fundamental type mismatch by replacing sizeof(void*) with the correct phys_addr_t type, ensuring that memory allocation properly accounts for the actual size requirements of physical address data structures. This correction maintains compatibility with both 32-bit and 64-bit architectures while ensuring proper memory management in the EFI capsule loading process. The resolution demonstrates the importance of proper type safety in kernel code and highlights the need for thorough testing across different architectural platforms when dealing with memory allocation and physical address handling in low-level system components.