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.
Metrics
Affected Vendors & Products
References
History
Thu, 02 Oct 2025 12:15:00 +0000
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threat_severity
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cvssV3_1
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Thu, 02 Oct 2025 09:00:00 +0000
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Linux
Linux linux Kernel |
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Vendors & Products |
Linux
Linux linux Kernel |
Wed, 01 Oct 2025 08:00:00 +0000
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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. | |
Title | bpf: Fix out-of-bounds dynptr write in bpf_crypto_crypt | |
References |
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Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-10-01T07:44:39.423Z
Reserved: 2025-04-16T07:20:57.147Z
Link: CVE-2025-39917

No data.

Status : Received
Published: 2025-10-01T08:15:34.887
Modified: 2025-10-01T08:15:34.887
Link: CVE-2025-39917


Updated: 2025-10-02T08:40:06Z