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Ari KauppiJ. Bruce Fields
Ari Kauppi
authored and
J. Bruce Fields
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nfsd: fix undefined behavior in nfsd4_layout_verify
UBSAN: Undefined behaviour in fs/nfsd/nfs4proc.c:1262:34 shift exponent 128 is too large for 32-bit type 'int' Depending on compiler+architecture, this may cause the check for layout_type to succeed for overly large values (which seems to be the case with amd64). The large value will be later used in de-referencing nfsd4_layout_ops for function pointers. Reported-by: Jani Tuovila <tuovila@synopsys.com> Signed-off-by: Ari Kauppi <ari@synopsys.com> [colin.king@canonical.com: use LAYOUT_TYPE_MAX instead of 32] Cc: stable@vger.kernel.org Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Diff for: fs/nfsd/nfs4proc.c

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Original file line numberDiff line numberDiff line change
@@ -1259,7 +1259,8 @@ nfsd4_layout_verify(struct svc_export *exp, unsigned int layout_type)
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return NULL;
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}
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if (!(exp->ex_layout_types & (1 << layout_type))) {
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if (layout_type >= LAYOUT_TYPE_MAX ||
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!(exp->ex_layout_types & (1 << layout_type))) {
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dprintk("%s: layout type %d not supported\n",
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__func__, layout_type);
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return NULL;

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