CVE-2025-39917 - bpf: Fix out-of-bounds dynptr write in bpf_crypto_crypt

CVE-2025-39917 - bpf: Fix out-of-bounds dynptr write in bpf_crypto_crypt

https://cvefeed.io/rssfeed/latest.atom / Wed, 10/01/2025 - 11:41
CVE ID : CVE-2025-39917
Published : Oct. 1, 2025, 8:15 a.m. | 1 hour, 17 minutes ago
Description : In the Linux kernel, the following vulnerability has been resolved: bpf: Fix out-of-bounds dynptr write in bpf_crypto_crypt Stanislav reported that in bpf_crypto_crypt() the destination dynptr's size is not validated to be at least as large as the source dynptr's size before calling into the crypto backend with 'len = src_len'. This can result in an OOB write when the destination is smaller than the source. Concretely, in mentioned function, psrc and pdst are both linear buffers fetched from each dynptr: psrc = __bpf_dynptr_data(src, src_len); [...] pdst = __bpf_dynptr_data_rw(dst, dst_len); [...] err = decrypt ? ctx->type->decrypt(ctx->tfm, psrc, pdst, src_len, piv) : ctx->type->encrypt(ctx->tfm, psrc, pdst, src_len, piv); The crypto backend expects pdst to be large enough with a src_len length that can be written. Add an additional src_len > dst_len check and bail out if it's the case. Note that these kfuncs are accessible under root privileges only.
Severity: 0.0 | NA
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