Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: SUNRPC: harden gss_unwrap_resp_priv length checks gss_unwrap_resp_priv() validates the RPCSEC_GSS opaque length with offset = (u8 *)(p) - (u8 *)head->iov_base; if (offset + opaque_len > rcv_buf->len) goto unwrap_failed; maj_stat = gss_unwrap(ctx->gc_gss_ctx, offset, offset + opaque_len, rcv_buf); Both operands are u32 and the sum is computed in u32. A reply with opaque_len near 0xffffffff makes offset + opaque_len wrap to a small value that is below rcv_buf->len, so the bound check passes and gss_unwrap() is called with end < begin. The check also lacks a lower bound, so any opaque_len in [0, GSS_KRB5_TOK_HDR_LEN) is accepted and forwarded to gss_krb5_unwrap_v2(), whose pre-decrypt header reads at ptr+4 and ptr+6 then run past the token. A krb5p NFS server returning a crafted RPCSEC_GSS reply can drive the client into out-of-bounds reads in gss_krb5_unwrap_v2() and the rotate_left() loop that follows. Fix by replacing the single combined check with three guards that are safe in u32 arithmetic and that enforce the RFC 4121 minimum outer token length: if (offset > rcv_buf->len) goto unwrap_failed; if (opaque_len > rcv_buf->len - offset) goto unwrap_failed; if (opaque_len < GSS_KRB5_TOK_HDR_LEN) goto unwrap_failed; The first guard makes the subtraction in the second guard unconditionally safe; offset is derived from a successful xdr_inline_decode() in the head kvec, so in practice it already satisfies the bound. The floor mirrors the server-side check added in commit 5b757c2e57a5 ("SUNRPC: svcauth_gss: enforce krb5 token minimum length").
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf before 3691c4b3488d8ca046b9941e5be30c626dbbbb50; affected 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf before 85fa6b12e8f439739ac36ef2aad925f37c8b976a; affected 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf before 401f6a5b338d05bb1069ad814d9f77e3c367854f; affected 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf before 81fd7654a8429718adfcb2a7e03496077f547ed0; affected 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf before 89a15a50f84d32d4b99db86f957427fcbe20a99a; affected 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf before ebcbd2523a8524c3d24e111cdbed8e271d910269; affected 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf before d395c30d570ca6168f0297b191709927d1258273; affected 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf before 87831b92112c81db251d46756d65daa4f91af6a2 |
| Linux / Linux | affected 2.6.15; unaffected 0 before 2.6.15; unaffected 5.10.270 through 5.10.*; unaffected 5.15.221 through 5.15.*; unaffected 6.1.188 through 6.1.*; unaffected 6.6.157 through 6.6.*; unaffected 6.12.109 through 6.12.*; unaffected 6.18.50 through 6.18.*; unaffected 7.2.4 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/3691c4b3488d8ca046b9941e5be30c626dbbbb50
- https://git.kernel.org/stable/c/85fa6b12e8f439739ac36ef2aad925f37c8b976a
- https://git.kernel.org/stable/c/401f6a5b338d05bb1069ad814d9f77e3c367854f
- https://git.kernel.org/stable/c/81fd7654a8429718adfcb2a7e03496077f547ed0
- https://git.kernel.org/stable/c/89a15a50f84d32d4b99db86f957427fcbe20a99a
- https://git.kernel.org/stable/c/ebcbd2523a8524c3d24e111cdbed8e271d910269
- https://git.kernel.org/stable/c/d395c30d570ca6168f0297b191709927d1258273
- https://git.kernel.org/stable/c/87831b92112c81db251d46756d65daa4f91af6a2
ADP enrichment
No English description supplied.
No references supplied.