fix ctx_sz bound for prehash signing

h2parson · h2parson · commit 2e9712c14600 · 2025-07-29T10:49:31.000-04:00
Signed-off-by: h2parson &lt;h2parson@uwaterloo.ca&gt;
diff --git a/slh_prehash.c b/slh_prehash.c
@@ -47,7 +47,7 @@ static size_t hash_slh_dsa_pad(uint8_t *mp, const uint8_t *m, size_t m_sz,
   const uint8_t shake_256_oid[11] = {0x06, 0x09, 0x60, 0x86, 0x48, 0x01,
                                      0x65, 0x03, 0x04, 0x02, 0x0C};
 
-  if (ctx_sz > 256)
+  if (ctx_sz > 255)
   {
     return 0;
   }

Original file line number	Diff line number	Diff line change
`@@ -47,7 +47,7 @@ static size_t hash_slh_dsa_pad(uint8_t mp, const uint8_t m, size_t m_sz,`
`47`	`47`	`const uint8_t shake_256_oid[11] = {0x06, 0x09, 0x60, 0x86, 0x48, 0x01,`
`48`	`48`	`0x65, 0x03, 0x04, 0x02, 0x0C};`
`49`	`49`
`50`		`- if (ctx_sz > 256)`
	`50`	`+ if (ctx_sz > 255)`
`51`	`51`	`{`
`52`	`52`	`return 0;`
`53`	`53`	`}`