Linux Kernel up to 6.12.4 ip_vs_protocol_init uninitialized pointer

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.12.4 and classified as problematic. Affected by this issue is the function ip_vs_protocol_init. This manipulation causes uninitialized pointer. The identification of this vulnerability is CVE-2024-53680. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as problematic was found in Linux Kernel up to 6.12.4. Affected by this vulnerability is the function ip_vs_protocol_init. The manipulation with an unknown input leads to a uninitialized pointer vulnerability. The CWE definition for the vulnerability is CWE-824. The product accesses or uses a pointer that has not been initialized. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ipvs: fix UB due to uninitialized stack access in ip_vs_protocol_init() Under certain kernel configurations when building with Clang/LLVM, the compiler does not generate a return or jump as the terminator instruction for ip_vs_protocol_init(), triggering the following objtool warning during build time: vmlinux.o: warning: objtool: ip_vs_protocol_init() falls through to next function __initstub__kmod_ip_vs_rr__935_123_ip_vs_rr_init6() At runtime, this either causes an oops when trying to load the ipvs module or a boot-time panic if ipvs is built-in. This same issue has been reported by the Intel kernel test robot previously. Digging deeper into both LLVM and the kernel code reveals this to be a undefined behavior problem. ip_vs_protocol_init() uses a on-stack buffer of 64 chars to store the registered protocol names and leaves it uninitialized after definition. The function calls strnlen() when concatenating protocol names into the buffer. With CONFIG_FORTIFY_SOURCE strnlen() performs an extra step to check whether the last byte of the input char buffer is a null character (commit 3009f891bb9f ("fortify: Allow strlen() and strnlen() to pass compile-time known lengths")). This, together with possibly other configurations, cause the following IR to be generated: define hidden i32 @ip_vs_protocol_init() local_unnamed_addr #5 section ".init.text" align 16 !kcfi_type !29 { %1 = alloca [64 x i8], align 16 ... 14: ; preds = %11 %15 = getelementptr inbounds i8, ptr %1, i64 63 %16 = load i8, ptr %15, align 1 %17 = tail call i1 @llvm.is.constant.i8(i8 %16) %18 = icmp eq i8 %16, 0 %19 = select i1 %17, i1 %18, i1 false br i1 %19, label %20, label %23 20: ; preds = %14 %21 = call i64 @strlen(ptr noundef nonnull dereferenceable(1) %1) #23 ... 23: ; preds = %14, %11, %20 %24 = call i64 @strnlen(ptr noundef nonnull dereferenceable(1) %1, i64 noundef 64) #24 ... } The above code calculates the address of the last char in the buffer (value %15) and then loads from it (value %16). Because the buffer is never initialized, the LLVM GVN pass marks value %16 as undefined: %13 = getelementptr inbounds i8, ptr %1, i64 63 br i1 undef, label %14, label %17 This gives later passes (SCCP, in particular) more DCE opportunities by propagating the undef value further, and eventually removes everything after the load on the uninitialized stack location: define hidden i32 @ip_vs_protocol_init() local_unnamed_addr #0 section ".init.text" align 16 !kcfi_type !11 { %1 = alloca [64 x i8], align 16 ... 12: ; preds = %11 %13 = getelementptr inbounds i8, ptr %1, i64 63 unreachable } In this way, the generated native code will just fall through to the next function, as LLVM does not generate any code for the unreachable IR instruction and leaves the function without a terminator. Zero the on-stack buffer to avoid this possible UB.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2024-53680 since 01/09/2025. The exploitation appears to be easy. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 216985 (Debian dla-4076 : linux-config-6.1 - security update), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.4.287, 5.10.231, 5.15.174, 6.1.120, 6.6.66 or 6.12.5 eliminates this vulnerability. Applying the patch 31d1ddc1ce8e8d3f101a679243abb42a313ee88a/0b2cbed82b7c6504a8a0fbd181f92dd56b432c12/d6e1776f51c95827142f1d7064118e255e2deec1/664d0feab92495b6a27edc3d1119e232c0fe8b2b/124834133b32f9386bb2d8581d9ab92f65e951e4/48130002e64fd191b7d18efeb4d253fcc23e4688/146b6f1112eb30a19776d6c323c994e9d67790db is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (216985) and CERT Bund (WID-SEC-2025-1439). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

• SUSE Linux
• Dell Secure Connect Gateway

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.4.286
• 5.10.230
• 5.15.173
• 6.1.119
• 6.6.0
• 6.6.1
• 6.6.2
• 6.6.3
• 6.6.4
• 6.6.5
• 6.6.6
• 6.6.7
• 6.6.8
• 6.6.9
• 6.6.10
• 6.6.11
• 6.6.12
• 6.6.13
• 6.6.14
• 6.6.15
• 6.6.16
• 6.6.17
• 6.6.18
• 6.6.19
• 6.6.20
• 6.6.21
• 6.6.22
• 6.6.23
• 6.6.24
• 6.6.25
• 6.6.26
• 6.6.27
• 6.6.28
• 6.6.29
• 6.6.30
• 6.6.31
• 6.6.32
• 6.6.33
• 6.6.34
• 6.6.35
• 6.6.36
• 6.6.37
• 6.6.38
• 6.6.39
• 6.6.40
• 6.6.41
• 6.6.42
• 6.6.43
• 6.6.44
• 6.6.45
• 6.6.46
• 6.6.47
• 6.6.48
• 6.6.49
• 6.6.50
• 6.6.51
• 6.6.52
• 6.6.53
• 6.6.54
• 6.6.55
• 6.6.56
• 6.6.57
• 6.6.58
• 6.6.59
• 6.6.60
• 6.6.61
• 6.6.62
• 6.6.63
• 6.6.64
• 6.6.65
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

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