DOC: clarify matching strings on binary fetches
Add clarification and example to string matching on binary samples,
as comparison stops at first null byte due to strncmp behaviour.
Backporting all the way down to 1.5 is suggested as it might save
from headaches.
(cherry picked from commit cb250fc9843a335fffe44ed6b15570e5b7cd2a35)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 31f3f5e5fecc6dcec08497b06df8267aad62e0ae)
Signed-off-by: Willy Tarreau <w@1wt.eu>
diff --git a/doc/configuration.txt b/doc/configuration.txt
index b37aac0..121e017 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -13534,6 +13534,14 @@
to match the string "-i", either set it second, or pass the "--" flag
before the first string. Same applies of course to match the string "--".
+Do not use string matches for binary fetches which might contain null bytes
+(0x00), as the comparison stops at the occurrence of the first null byte.
+Instead, convert the binary fetch to a hex string with the hex converter first.
+
+Example:
+ # matches if the string <tag> is present in the binary sample
+ acl tag_found req.payload(0,0),hex -m sub 3C7461673E
+
7.1.4. Matching regular expressions (regexes)
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