From 91027d0a7a0e309b94674923dc1b245b709b5c1e Mon Sep 17 00:00:00 2001 From: Chris Down Date: Tue, 15 Jun 2021 17:52:45 +0100 Subject: 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 ++++ 1 file changed, 4 insertions(+) (limited to 'lib/string_helpers.c') 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 -- cgit