CVE-2025-37984

Summary

In the Linux kernel, the following vulnerability has been resolved:

crypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP()

Herbert notes that DIV_ROUND_UP() may overflow unnecessarily if an ecdsa implementation's ->key_size() callback returns an unusually large value. Herbert instead suggests (for a division by 8):

X / 8 + !!(X & 7)

Based on this formula, introduce a generic DIV_ROUND_UP_POW2() macro and use it in lieu of DIV_ROUND_UP() for ->key_size() return values.

Additionally, use the macro in ecc_digits_from_bytes(), whose "nbytes" parameter is a ->key_size() return value in some instances, or a user-specified ASN.1 length in the case of ecdsa_get_signature_rs().

Affected Software

VendorProductVersion RangeStatus
LinuxLinux55779f26eab9af12474a447001bd17070f055712 < f02f0218be412cff1c844addf58e002071be298baffected
LinuxLinuxc6ab5c915da460c0397960af3c308386c3f3247b < f2133b849ff273abddb6da622daddd8f6f6fa448affected
LinuxLinuxc6ab5c915da460c0397960af3c308386c3f3247b < 921b8167f10708e38080f84e195cdc68a7a561f1affected
LinuxLinuxc6ab5c915da460c0397960af3c308386c3f3247b < b16510a530d1e6ab9683f04f8fb34f2e0f538275affected
LinuxLinux6.6.70 < 6.6.99affected
LinuxLinux6.10affected
LinuxLinux0 < 6.10unaffected
LinuxLinux6.6.99 <= 6.6.*unaffected
LinuxLinux6.12.39 <= 6.12.*unaffected
LinuxLinux6.14.5 <= 6.14.*unaffected
LinuxLinux6.15 <= *unaffected

Weaknesses

References