From 91027d0a7a0e309b94674923dc1b245b709b5c1e Mon Sep 17 00:00:00 2001 From: Chris Down Date: Tue, 15 Jun 2021 17:52:45 +0100 Subject: [PATCH] string_helpers: Escape double quotes in escape_special From an abstract point of view, escape_special's counterpart, unescape_special, already handles the unescaping of blackslashed double quote sequences. As a more practical example, printk indexing is an example case where this is already practically useful. Compare an example with `ESCAPE_SPECIAL | ESCAPE_SPACE`, with quotes not escaped: [root@ktst ~]# grep drivers/pci/pci-stub.c:69 /sys/kernel/debug/printk/index/vmlinux <4> drivers/pci/pci-stub.c:69 pci_stub_init "pci-stub: invalid ID string "%s"\n" ...and the same after this patch: [root@ktst ~]# grep drivers/pci/pci-stub.c:69 /sys/kernel/debug/printk/index/vmlinux <4> drivers/pci/pci-stub.c:69 pci_stub_init "pci-stub: invalid ID string \"%s\"\n" One can of course, alternatively, use ESCAPE_APPEND with a quote in @only, but without this patch quotes are coerced into hex or octal which can hurt readability quite significantly. I've checked uses of ESCAPE_SPECIAL and %pE across the codebase, and I'm pretty confident that this shouldn't affect any stable interfaces. Signed-off-by: Chris Down Reviewed-by: Andy Shevchenko Reviewed-by: Petr Mladek Cc: Rasmus Villemoes Acked-by: Andy Shevchenko Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/af144c5b75e41ce417386253ba2694456bc04118.1623775748.git.chris@chrisdown.name --- lib/string_helpers.c | 4 ++++ lib/test-string_helpers.c | 14 +++++++------- 2 files changed, 11 insertions(+), 7 deletions(-) diff --git a/lib/string_helpers.c b/lib/string_helpers.c index 5a35c7e16e96..3806a52ce697 100644 --- a/lib/string_helpers.c +++ b/lib/string_helpers.c @@ -361,6 +361,9 @@ static bool escape_special(unsigned char c, char **dst, char *end) case '\e': to = 'e'; break; + case '"': + to = '"'; + break; default: return false; } @@ -474,6 +477,7 @@ static bool escape_hex(unsigned char c, char **dst, char *end) * '\t' - horizontal tab * '\v' - vertical tab * %ESCAPE_SPECIAL: + * '\"' - double quote * '\\' - backslash * '\a' - alert (BEL) * '\e' - escape diff --git a/lib/test-string_helpers.c b/lib/test-string_helpers.c index 2185d71704f0..437d8e6b7cb1 100644 --- a/lib/test-string_helpers.c +++ b/lib/test-string_helpers.c @@ -140,13 +140,13 @@ static const struct test_string_2 escape0[] __initconst = {{ },{ .in = "\\h\\\"\a\e\\", .s1 = {{ - .out = "\\\\h\\\\\"\\a\\e\\\\", + .out = "\\\\h\\\\\\\"\\a\\e\\\\", .flags = ESCAPE_SPECIAL, },{ - .out = "\\\\\\150\\\\\\042\\a\\e\\\\", + .out = "\\\\\\150\\\\\\\"\\a\\e\\\\", .flags = ESCAPE_SPECIAL | ESCAPE_OCTAL, },{ - .out = "\\\\\\x68\\\\\\x22\\a\\e\\\\", + .out = "\\\\\\x68\\\\\\\"\\a\\e\\\\", .flags = ESCAPE_SPECIAL | ESCAPE_HEX, },{ /* terminator */ @@ -157,10 +157,10 @@ static const struct test_string_2 escape0[] __initconst = {{ .out = "\eb \\C\007\"\x90\\r]", .flags = ESCAPE_SPACE, },{ - .out = "\\eb \\\\C\\a\"\x90\r]", + .out = "\\eb \\\\C\\a\\\"\x90\r]", .flags = ESCAPE_SPECIAL, },{ - .out = "\\eb \\\\C\\a\"\x90\\r]", + .out = "\\eb \\\\C\\a\\\"\x90\\r]", .flags = ESCAPE_SPACE | ESCAPE_SPECIAL, },{ .out = "\\033\\142\\040\\134\\103\\007\\042\\220\\015\\135", @@ -169,10 +169,10 @@ static const struct test_string_2 escape0[] __initconst = {{ .out = "\\033\\142\\040\\134\\103\\007\\042\\220\\r\\135", .flags = ESCAPE_SPACE | ESCAPE_OCTAL, },{ - .out = "\\e\\142\\040\\\\\\103\\a\\042\\220\\015\\135", + .out = "\\e\\142\\040\\\\\\103\\a\\\"\\220\\015\\135", .flags = ESCAPE_SPECIAL | ESCAPE_OCTAL, },{ - .out = "\\e\\142\\040\\\\\\103\\a\\042\\220\\r\\135", + .out = "\\e\\142\\040\\\\\\103\\a\\\"\\220\\r\\135", .flags = ESCAPE_SPACE | ESCAPE_SPECIAL | ESCAPE_OCTAL, },{ .out = "\eb \\C\007\"\x90\r]",