Re: [PATCH 30/32] strlen.3, wcslen.3: Add recommendations for safer variants
From: Michael Kerrisk (man-pages) <hidden>
Date: 2021-08-07 23:45:31
Hello Alex, I see there was a rather long mail thread that led to this patch. The patch definitely deserves a commit message. See also below. On 7/28/21 10:20 PM, Alejandro Colomar wrote:
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Reported-by: Jonny Grant <redacted> Signed-off-by: Alejandro Colomar <redacted> --- man3/strlen.3 | 6 ++++++ man3/wcslen.3 | 9 ++++++++- 2 files changed, 14 insertions(+), 1 deletion(-)diff --git a/man3/strlen.3 b/man3/strlen.3 index dea4c1050..78783c446 100644 --- a/man3/strlen.3 +++ b/man3/strlen.3@@ -66,6 +66,12 @@ T} Thread safety MT-Safe .sp 1 .SH CONFORMING TO POSIX.1-2001, POSIX.1-2008, C89, C99, C11, SVr4, 4.3BSD. +.SH NOTES +.SS strnlen(3) +If the input buffer size is known, +it is probably better to use +.BR strnlen (3), +which can prevent reading past the end of the array.
I hesitate slightly about this. strlen() is in the C standard, but strnlen() is not. What do you think; do we need to care? Thanks, Michael
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.SH SEE ALSO .BR string (3), .BR strnlen (3),diff --git a/man3/wcslen.3 b/man3/wcslen.3 index af3fcb9ca..fe1d6331b 100644 --- a/man3/wcslen.3 +++ b/man3/wcslen.3@@ -58,5 +58,12 @@ T} Thread safety MT-Safe .sp 1 .SH CONFORMING TO POSIX.1-2001, POSIX.1-2008, C99. +.SH NOTES +.SS wcsnlen(3) +If the input buffer size is known, +it is probably better to use +.BR wcsnlen (3), +which can prevent reading past the end of the array. .SH SEE ALSO -.BR strlen (3) +.BR strlen (3), +.BR wcsnlen (3)
-- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/