Messages in this thread | | | From | "Yang, Shunyong" <> | Subject | Re: [此邮件可能存在风险] [PATCH v2 7/9] lib/vsprintf: Replace space with ' ' bef ore crng is ready | Date | Tue, 20 Feb 2018 02:57:19 +0000 |
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Hi, Andy,
Many thanks for the change. I am on Chinese New Year travel and slow response. :-)
Thanks. Shunyong.
On Fri, 2018-02-16 at 23:07 +0200, Andy Shevchenko wrote: > From: Shunyong Yang <shunyong.yang@hxt-semitech.com> > > Before crng is ready, output of "%p" composes of "(ptrval)" and > left padding spaces for alignment as no random address can be > generated. This seems a little strange when default string width > is larger than strlen("(ptrval)"). > > For example, when irq domain names are built with "%p", the nodes > under /sys/kernel/debug/irq/domains like this on AArch64 system, > > [root@y irq]# ls domains/ > default irqchip@ (ptrval)-2 > irqchip@ (ptrval)-4 \_SB_.TCS0.QIC1 \_SB_.TCS0.QIC3 > irqchip@ (ptrval) irqchip@ (ptrval)-3 > \_SB_.TCS0.QIC0 \_SB_.TCS0.QIC2 > > The name "irqchip@ (ptrval)-2" is not so readable in console > output. > > This patch replaces space with readable "_" when output needs > padding. > Following is the output after applying the patch, > > [root@y domains]# ls > default irqchip@(____ptrval____)-2 > irqchip@(____ptrval____)-4 \_SB_.TCS0.QIC1 \_SB_.TCS0.QIC3 > irqchip@(____ptrval____) irqchip@(____ptrval____)-3 \_SB_.TCS0.QIC0 > \_SB_.TCS0.QIC2 > > There is same problem in some subsystem's dmesg output. Moreover, > someone may call "%p" in a similar case. In addition, the timing of > crng initialization done may vary on different system. So, the change > is made in vsprintf.c. > > Cc: Joey Zheng <yu.zheng@hxt-semitech.com> > Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> > Signed-off-by: Shunyong Yang <shunyong.yang@hxt-semitech.com> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > --- > lib/vsprintf.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/lib/vsprintf.c b/lib/vsprintf.c > index 9004bbb3d84d..97be2d07297a 100644 > --- a/lib/vsprintf.c > +++ b/lib/vsprintf.c > @@ -1681,12 +1681,13 @@ early_initcall(initialize_ptr_random); > /* Maps a pointer to a 32 bit unique identifier. */ > static char *ptr_to_id(char *buf, char *end, void *ptr, struct > printf_spec spec) > { > + const char *str = sizeof(ptr) == 8 ? "(____ptrval____)" : > "(ptrval)"; > unsigned long hashval; > > if (unlikely(!have_filled_random_ptr_key)) { > spec.field_width = 2 * sizeof(ptr); > /* string length must be less than default_width */ > - return string(buf, end, "(ptrval)", spec); > + return string(buf, end, str, spec); > } > > #ifdef CONFIG_64BIT | |