From be89c712679a693d8626eae1131f6f7e3d672bf5 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Sat, 22 Feb 2025 10:49:19 +0100
Subject: [PATCH] var: add a 'd64' function that can base64 decode a string
Verified in test 455 and 487.
If the provided string cannot be base64-decoded, it will instead use
"[d64-fail]" (without the quotes).
Documented
Ref: #16288
---
docs/cmdline-opts/_VARIABLES.md | 8 ++---
docs/cmdline-opts/variable.md | 23 ++++++++++++---
src/var.c | 23 +++++++++++++++
tests/data/Makefile.am | 2 +-
tests/data/test455 | 4 +--
tests/data/test487 | 52 +++++++++++++++++++++++++++++++++
6 files changed, 101 insertions(+), 11 deletions(-)
create mode 100644 tests/data/test487
diff --git a/docs/cmdline-opts/_VARIABLES.md b/docs/cmdline-opts/_VARIABLES.md
index e46b675531..62b56ca38c 100644
--- a/docs/cmdline-opts/_VARIABLES.md
+++ b/docs/cmdline-opts/_VARIABLES.md
@@ -27,10 +27,10 @@ set:
When expanding variables, curl supports a set of functions that can make the
variable contents more convenient to use. It can trim leading and trailing
white space with `trim`, it can output the contents as a JSON quoted string
-with `json`, URL encode the string with `url` or base64 encode it with `b64`.
-To apply functions to a variable expansion, add them colon separated to the
-right side of the variable. Variable content holding null bytes that are not
-encoded when expanded cause error.
+with `json`, URL encode the string with `url`, base64 encode it with `b64` and
+base64 decode it with `64dec`. To apply functions to a variable expansion, add
+them colon separated to the right side of the variable. Variable content
+holding null bytes that are not encoded when expanded cause error.
Example: get the contents of a file called $HOME/.secret into a variable
called "fix". Make sure that the content is trimmed and percent-encoded when
diff --git a/docs/cmdline-opts/variable.md b/docs/cmdline-opts/variable.md
index 1a0e70e209..b6bf4e728c 100644
--- a/docs/cmdline-opts/variable.md
+++ b/docs/cmdline-opts/variable.md
@@ -66,30 +66,45 @@ error.
Available functions:
-## trim
+## `trim`
+
removes all leading and trailing white space.
Example:
curl --expand-url https://example.com/{{var:trim}}
-## json
+## `json`
+
outputs the content using JSON string quoting rules.
Example:
curl --expand-data {{data:json}} https://example.com
-## url
+## `url`
+
shows the content URL (percent) encoded.
Example:
curl --expand-url https://example.com/{{path:url}}
-## b64
+## `b64`
+
expands the variable base64 encoded
Example:
curl --expand-url https://example.com/{{var:b64}}
+
+## `64dec`
+
+decodes a base64 encoded character sequence. If the sequence is not possible
+to decode, it instead outputs `64dec-fail`
+
+Example:
+
+ curl --expand-url https://example.com/{{var:64dec}}
+
+(Added in 8.13.0)
diff --git a/src/var.c b/src/var.c
index f4b221e74a..5ac7506891 100644
--- a/src/var.c
+++ b/src/var.c
@@ -91,6 +91,8 @@ static const struct tool_var *varcontent(struct GlobalConfig *global,
#define FUNC_URL_LEN (sizeof(FUNC_URL) - 1)
#define FUNC_B64 "b64"
#define FUNC_B64_LEN (sizeof(FUNC_B64) - 1)
+#define FUNC_64DEC "64dec" /* base64 decode */
+#define FUNC_64DEC_LEN (sizeof(FUNC_64DEC) - 1)
static ParameterError varfunc(struct GlobalConfig *global,
char *c, /* content */
@@ -179,6 +181,27 @@ static ParameterError varfunc(struct GlobalConfig *global,
break;
}
}
+ else if(FUNCMATCH(f, FUNC_64DEC, FUNC_64DEC_LEN)) {
+ f += FUNC_64DEC_LEN;
+ curlx_dyn_reset(out);
+ if(clen) {
+ unsigned char *enc;
+ size_t elen;
+ CURLcode result = curlx_base64_decode(c, &enc, &elen);
+ /* put it in the output */
+ if(result) {
+ if(curlx_dyn_add(out, "[64dec-fail]"))
+ err = PARAM_NO_MEM;
+ }
+ else {
+ if(curlx_dyn_addn(out, enc, elen))
+ err = PARAM_NO_MEM;
+ curl_free(enc);
+ }
+ if(err)
+ break;
+ }
+ }
else {
/* unsupported function */
errorf(global, "unknown variable function in '%.*s'",
diff --git a/tests/data/Makefile.am b/tests/data/Makefile.am
index 01fbe9b23e..6ce2879e9a 100644
--- a/tests/data/Makefile.am
+++ b/tests/data/Makefile.am
@@ -78,7 +78,7 @@ test444 test445 test446 test447 test448 test449 test450 test451 test452 \
test453 test454 test455 test456 test457 test458 test459 test460 test461 \
test462 test463 test467 test468 test469 test470 test471 test472 test473 \
test474 test475 test476 test477 test478 test479 test480 test481 test482 \
-test483 test484 test485 test486 \
+test483 test484 test485 test486 test487 \
test490 test491 test492 test493 test494 test495 test496 test497 test498 \
test499 test500 test501 test502 test503 test504 test505 test506 test507 \
test508 test509 test510 test511 test512 test513 test514 test515 test516 \
diff --git a/tests/data/test455 b/tests/data/test455
index ffe6bd14c1..7e468e7524 100644
--- a/tests/data/test455
+++ b/tests/data/test455
@@ -34,7 +34,7 @@ http
Variable using base64
</name>
<command>
---variable moby="Call me Ishmael" --expand-url "http://%HOSTIP:%HTTPPORT/{{moby:b64}}/%TESTNUMBER"
+--variable moby="Call me Ishmael" --variable what=%b64[white-whale]b64% --expand-url "http://%HOSTIP:%HTTPPORT/{{moby:b64}}/{{what:64dec}}/%TESTNUMBER"
</command>
</client>
@@ -42,7 +42,7 @@ Variable using base64
# Verify data after the test has been "shot"
<verify>
<protocol crlf="yes">
-GET /%b64[Call me Ishmael]b64%/%TESTNUMBER HTTP/1.1
+GET /%b64[Call me Ishmael]b64%/white-whale/%TESTNUMBER HTTP/1.1
Host: %HOSTIP:%HTTPPORT
User-Agent: curl/%VERSION
Accept: */*
diff --git a/tests/data/test487 b/tests/data/test487
new file mode 100644
index 0000000000..3ac508b2e5
--- /dev/null
+++ b/tests/data/test487
@@ -0,0 +1,52 @@
+<testcase>
+<info>
+<keywords>
+variables
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<data crlf="yes">
+HTTP/1.1 200 OK
+Date: Tue, 09 Nov 2010 14:49:00 GMT
+Server: test-server/fake
+Last-Modified: Tue, 13 Jun 2000 12:10:00 GMT
+ETag: "21025-dc7-39462498"
+Accept-Ranges: bytes
+Content-Length: 6
+Connection: close
+Content-Type: text/html
+Funny-head: yesyes
+
+-foo-
+</data>
+</reply>
+
+#
+# Client-side
+<client>
+<server>
+http
+</server>
+<name>
+Variable using 64dec with bad base64
+</name>
+<command>
+--variable what=not-base64-data --expand-url "http://%HOSTIP:%HTTPPORT/{{what:64dec}}/%TESTNUMBER" -g
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol crlf="yes">
+GET /[64dec-fail]/%TESTNUMBER HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+User-Agent: curl/%VERSION
+Accept: */*
+
+</protocol>
+</verify>
+</testcase>
--
GitLab