| Message ID | 20210611155953.3010-4-justin.he@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | make '%pD' print full path for file | expand |
On 11/06/2021 17.59, Jia He wrote: > After the behaviour of specifier '%pD' is changed to print full path > of struct file, the related test cases are also updated. > > Given the string is prepended from the end of the buffer, the check > of "wrote beyond the nul-terminator" should be skipped. Sorry, that is far from enough justification. I should probably have split the "wrote beyond nul-terminator" check in two: One that checks whether any memory beyond the buffer given to vsnprintf() was touched (including all the padding, but possibly more for the cases where we pass a known-too-short buffer), symmetric to the "wrote before buffer" check. And then another that checks the area between the '\0' and the end of the given buffer - I suppose that it's fair game for vsnprintf to use all of that as scratch space, and for that it could be ok to add that boolean knob. Rasmus
On Fri 2021-06-11 23:59:53, Jia He wrote: > After the behaviour of specifier '%pD' is changed to print full path > of struct file, the related test cases are also updated. > > Given the string is prepended from the end of the buffer, the check > of "wrote beyond the nul-terminator" should be skipped. > > Signed-off-by: Jia He <justin.he@arm.com> > --- > lib/test_printf.c | 26 +++++++++++++++++++++++++- > 1 file changed, 25 insertions(+), 1 deletion(-) > > diff --git a/lib/test_printf.c b/lib/test_printf.c > index ec0d5976bb69..3632bd6cf906 100644 > --- a/lib/test_printf.c > +++ b/lib/test_printf.c > @@ -78,7 +80,7 @@ do_test(int bufsize, const char *expect, int elen, > return 1; > } > > - if (memchr_inv(test_buffer + written + 1, FILL_CHAR, BUF_SIZE + PAD_SIZE - (written + 1))) { > + if (!is_prepend_buf && memchr_inv(test_buffer + written + 1, FILL_CHAR, BUF_SIZE + PAD_SIZE - (written + 1))) { > pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote beyond the nul-terminator\n", > bufsize, fmt); > return 1; > @@ -496,6 +498,27 @@ dentry(void) > test(" bravo/alfa| bravo/alfa", "%12pd2|%*pd2", &test_dentry[2], 12, &test_dentry[2]); > } > > +static struct vfsmount test_vfsmnt = {}; > + > +static struct file test_file __initdata = { > + .f_path = { .dentry = &test_dentry[2], > + .mnt = &test_vfsmnt, > + }, > +}; > + > +static void __init > +f_d_path(void) > +{ > + test("(null)", "%pD", NULL); > + test("(efault)", "%pD", PTR_INVALID); > + > + is_prepend_buf = true; > + test("/bravo/alfa |/bravo/alfa ", "%-14pD|%*pD", &test_file, -14, &test_file); > + test(" /bravo/alfa| /bravo/alfa", "%14pD|%*pD", &test_file, 14, &test_file); > + test(" /bravo/alfa|/bravo/alfa ", "%14pD|%-14pD", &test_file, &test_file); Please, add more test for scenarios when the path does not fit into the buffer or when there are no limitations, ... I still have to think about is_prepend_buf hack. > + is_prepend_buf = false; > +} > + > static void __init > struct_va_format(void) > { Best Regards, PEtr
Hi Rasmus > -----Original Message----- > From: Rasmus Villemoes <linux@rasmusvillemoes.dk> > Sent: Saturday, June 12, 2021 5:40 AM > To: Justin He <Justin.He@arm.com>; Petr Mladek <pmladek@suse.com>; Steven > Rostedt <rostedt@goodmis.org>; Sergey Senozhatsky > <senozhatsky@chromium.org>; Andy Shevchenko > <andriy.shevchenko@linux.intel.com>; Jonathan Corbet <corbet@lwn.net>; > Alexander Viro <viro@zeniv.linux.org.uk>; Linus Torvalds <torvalds@linux- > foundation.org> > Cc: Peter Zijlstra (Intel) <peterz@infradead.org>; Eric Biggers > <ebiggers@google.com>; Ahmed S. Darwish <a.darwish@linutronix.de>; linux- > doc@vger.kernel.org; linux-kernel@vger.kernel.org; linux- > fsdevel@vger.kernel.org > Subject: Re: [PATCH RFCv3 3/3] lib/test_printf: add test cases for '%pD' > > On 11/06/2021 17.59, Jia He wrote: > > After the behaviour of specifier '%pD' is changed to print full path > > of struct file, the related test cases are also updated. > > > > Given the string is prepended from the end of the buffer, the check > > of "wrote beyond the nul-terminator" should be skipped. > > Sorry, that is far from enough justification. > > I should probably have split the "wrote beyond nul-terminator" check in two: > > One that checks whether any memory beyond the buffer given to > vsnprintf() was touched (including all the padding, but possibly more > for the cases where we pass a known-too-short buffer), symmetric to the > "wrote before buffer" check. > > And then another that checks the area between the '\0' and the end of > the given buffer - I suppose that it's fair game for vsnprintf to use > all of that as scratch space, and for that it could be ok to add that > boolean knob. > Sorry, I could have thought sth like "write beyond the buffer" had been checked by old test cases, but seems not. I will split the "wrote beyond nul-terminator" check into 2 parts. One for Non-%pD case, the other for %pD. For %pD, it needs to check whether the space beyond test_buffer[] is written -- Cheers, Justin (Jia He) IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
Hi Petr > -----Original Message----- > From: Petr Mladek <pmladek@suse.com> > Sent: Monday, June 14, 2021 11:44 PM > To: Justin He <Justin.He@arm.com> > Cc: Steven Rostedt <rostedt@goodmis.org>; Sergey Senozhatsky > <senozhatsky@chromium.org>; Andy Shevchenko > <andriy.shevchenko@linux.intel.com>; Rasmus Villemoes > <linux@rasmusvillemoes.dk>; Jonathan Corbet <corbet@lwn.net>; Alexander > Viro <viro@zeniv.linux.org.uk>; Linus Torvalds <torvalds@linux- > foundation.org>; Peter Zijlstra (Intel) <peterz@infradead.org>; Eric > Biggers <ebiggers@google.com>; Ahmed S. Darwish <a.darwish@linutronix.de>; > linux-doc@vger.kernel.org; linux-kernel@vger.kernel.org; linux- > fsdevel@vger.kernel.org > Subject: Re: [PATCH RFCv3 3/3] lib/test_printf: add test cases for '%pD' > > On Fri 2021-06-11 23:59:53, Jia He wrote: > > After the behaviour of specifier '%pD' is changed to print full path > > of struct file, the related test cases are also updated. > > > > Given the string is prepended from the end of the buffer, the check > > of "wrote beyond the nul-terminator" should be skipped. > > > > Signed-off-by: Jia He <justin.he@arm.com> > > --- > > lib/test_printf.c | 26 +++++++++++++++++++++++++- > > 1 file changed, 25 insertions(+), 1 deletion(-) > > > > diff --git a/lib/test_printf.c b/lib/test_printf.c > > index ec0d5976bb69..3632bd6cf906 100644 > > --- a/lib/test_printf.c > > +++ b/lib/test_printf.c > > @@ -78,7 +80,7 @@ do_test(int bufsize, const char *expect, int elen, > > return 1; > > } > > > > - if (memchr_inv(test_buffer + written + 1, FILL_CHAR, BUF_SIZE + > PAD_SIZE - (written + 1))) { > > + if (!is_prepend_buf && memchr_inv(test_buffer + written + 1, > FILL_CHAR, BUF_SIZE + PAD_SIZE - (written + 1))) { > > pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote beyond the nul- > terminator\n", > > bufsize, fmt); > > return 1; > > @@ -496,6 +498,27 @@ dentry(void) > > test(" bravo/alfa| bravo/alfa", "%12pd2|%*pd2", &test_dentry[2], > 12, &test_dentry[2]); > > } > > > > +static struct vfsmount test_vfsmnt = {}; > > + > > +static struct file test_file __initdata = { > > + .f_path = { .dentry = &test_dentry[2], > > + .mnt = &test_vfsmnt, > > + }, > > +}; > > + > > +static void __init > > +f_d_path(void) > > +{ > > + test("(null)", "%pD", NULL); > > + test("(efault)", "%pD", PTR_INVALID); > > + > > + is_prepend_buf = true; > > + test("/bravo/alfa |/bravo/alfa ", "%-14pD|%*pD", &test_file, -14, > &test_file); > > + test(" /bravo/alfa| /bravo/alfa", "%14pD|%*pD", &test_file, 14, > &test_file); > > + test(" /bravo/alfa|/bravo/alfa ", "%14pD|%-14pD", &test_file, > &test_file); > > Please, add more test for scenarios when the path does not fit into > the buffer or when there are no limitations, ... Indeed, thanks -- Cheers, Justin (Jia He) IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
Hi Rasmus > -----Original Message----- > From: Justin He > Sent: Tuesday, June 15, 2021 3:06 PM > To: Rasmus Villemoes <linux@rasmusvillemoes.dk>; Petr Mladek > <pmladek@suse.com>; Steven Rostedt <rostedt@goodmis.org>; Sergey > Senozhatsky <senozhatsky@chromium.org>; Andy Shevchenko > <andriy.shevchenko@linux.intel.com>; Jonathan Corbet <corbet@lwn.net>; > Alexander Viro <viro@zeniv.linux.org.uk>; Linus Torvalds <torvalds@linux- > foundation.org> > Cc: Peter Zijlstra (Intel) <peterz@infradead.org>; Eric Biggers > <ebiggers@google.com>; Ahmed S. Darwish <a.darwish@linutronix.de>; linux- > doc@vger.kernel.org; linux-kernel@vger.kernel.org; linux- > fsdevel@vger.kernel.org > Subject: RE: [PATCH RFCv3 3/3] lib/test_printf: add test cases for '%pD' > > Hi Rasmus > > > -----Original Message----- > > From: Rasmus Villemoes <linux@rasmusvillemoes.dk> > > Sent: Saturday, June 12, 2021 5:40 AM > > To: Justin He <Justin.He@arm.com>; Petr Mladek <pmladek@suse.com>; Steven > > Rostedt <rostedt@goodmis.org>; Sergey Senozhatsky > > <senozhatsky@chromium.org>; Andy Shevchenko > > <andriy.shevchenko@linux.intel.com>; Jonathan Corbet <corbet@lwn.net>; > > Alexander Viro <viro@zeniv.linux.org.uk>; Linus Torvalds <torvalds@linux- > > foundation.org> > > Cc: Peter Zijlstra (Intel) <peterz@infradead.org>; Eric Biggers > > <ebiggers@google.com>; Ahmed S. Darwish <a.darwish@linutronix.de>; linux- > > doc@vger.kernel.org; linux-kernel@vger.kernel.org; linux- > > fsdevel@vger.kernel.org > > Subject: Re: [PATCH RFCv3 3/3] lib/test_printf: add test cases for '%pD' > > > > On 11/06/2021 17.59, Jia He wrote: > > > After the behaviour of specifier '%pD' is changed to print full path > > > of struct file, the related test cases are also updated. > > > > > > Given the string is prepended from the end of the buffer, the check > > > of "wrote beyond the nul-terminator" should be skipped. > > > > Sorry, that is far from enough justification. > > > > I should probably have split the "wrote beyond nul-terminator" check in > two: > > > > One that checks whether any memory beyond the buffer given to > > vsnprintf() was touched (including all the padding, but possibly more > > for the cases where we pass a known-too-short buffer), symmetric to the > > "wrote before buffer" check. > > > > And then another that checks the area between the '\0' and the end of > > the given buffer - I suppose that it's fair game for vsnprintf to use > > all of that as scratch space, and for that it could be ok to add that > > boolean knob. > > > Sorry, I could have thought sth like "write beyond the buffer" had been > checked by > old test cases, but seems not. > I will split the "wrote beyond nul-terminator" check into 2 parts. One for > Non-%pD case, the other for %pD. > > For %pD, it needs to check whether the space beyond test_buffer[] is > written > > Another question is about precision, Do you think I should add some test cases e.g. "%.10pD" here? I once added some, but the gcc report warning: warning: precision used with '%p' gnu_printf What do you think of that? -- Cheers, Justin (Jia He) IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
On 15/06/2021 09.06, Justin He wrote: > Hi Rasmus > >> -----Original Message----- >> From: Rasmus Villemoes <linux@rasmusvillemoes.dk> >> Sent: Saturday, June 12, 2021 5:40 AM >> To: Justin He <Justin.He@arm.com>; Petr Mladek <pmladek@suse.com>; Steven >> Rostedt <rostedt@goodmis.org>; Sergey Senozhatsky >> <senozhatsky@chromium.org>; Andy Shevchenko >> <andriy.shevchenko@linux.intel.com>; Jonathan Corbet <corbet@lwn.net>; >> Alexander Viro <viro@zeniv.linux.org.uk>; Linus Torvalds <torvalds@linux- >> foundation.org> >> Cc: Peter Zijlstra (Intel) <peterz@infradead.org>; Eric Biggers >> <ebiggers@google.com>; Ahmed S. Darwish <a.darwish@linutronix.de>; linux- >> doc@vger.kernel.org; linux-kernel@vger.kernel.org; linux- >> fsdevel@vger.kernel.org >> Subject: Re: [PATCH RFCv3 3/3] lib/test_printf: add test cases for '%pD' >> >> On 11/06/2021 17.59, Jia He wrote: >>> After the behaviour of specifier '%pD' is changed to print full path >>> of struct file, the related test cases are also updated. >>> >>> Given the string is prepended from the end of the buffer, the check >>> of "wrote beyond the nul-terminator" should be skipped. >> >> Sorry, that is far from enough justification. >> >> I should probably have split the "wrote beyond nul-terminator" check in two: >> >> One that checks whether any memory beyond the buffer given to >> vsnprintf() was touched (including all the padding, but possibly more >> for the cases where we pass a known-too-short buffer), symmetric to the >> "wrote before buffer" check. >> >> And then another that checks the area between the '\0' and the end of >> the given buffer - I suppose that it's fair game for vsnprintf to use >> all of that as scratch space, and for that it could be ok to add that >> boolean knob. >> > Sorry, I could have thought sth like "write beyond the buffer" had been checked by > old test cases, but seems not. It does. Before each (sub)test, we have (assume PAD_SIZE=4, BUF_SIZE=12) | <- alloced_buffer -> | | PAD | test_buffer | PAD | | **** | ************ | **** | Then after snprintf(buf, 10, "pizza") we have | <- alloced_buffer -> | | PAD | test_buffer | PAD | | **** | pizza0****** | **** | A B C D E (with 0 being the nul character). Then if (memchr_inv(alloced_buffer, FILL_CHAR, PAD_SIZE)) { checks whether snprint wrote anything between A and B, while if (memchr_inv(test_buffer + written + 1, FILL_CHAR, BUF_SIZE + PAD_SIZE - (written + 1))) { checks whether there was a write between C and E. What I'm saying is that I can see it being reasonable for (some helper inside) snprintf to actually write something beyond C, but certainly never beyond D. So the "wrote beyond" test could be split up, with the first half possibly being allowed to be opt-out for certain test cases. > I will split the "wrote beyond nul-terminator" check into 2 parts. One for > Non-%pD case, the other for %pD. > > For %pD, it needs to check whether the space beyond test_buffer[] is written No, that's not the right way to do this. Let me cook up a patch you can include in your series. Rasmus
On 15/06/2021 09.07, Justin He wrote: > Hi Petr > >>> +static void __init >>> +f_d_path(void) >>> +{ >>> + test("(null)", "%pD", NULL); >>> + test("(efault)", "%pD", PTR_INVALID); >>> + >>> + is_prepend_buf = true; >>> + test("/bravo/alfa |/bravo/alfa ", "%-14pD|%*pD", &test_file, -14, >> &test_file); >>> + test(" /bravo/alfa| /bravo/alfa", "%14pD|%*pD", &test_file, 14, >> &test_file); >>> + test(" /bravo/alfa|/bravo/alfa ", "%14pD|%-14pD", &test_file, >> &test_file); >> >> Please, add more test for scenarios when the path does not fit into >> the buffer or when there are no limitations, ... > > Indeed, thanks Doesn't the existing test() helper do this for you automatically? /* * Every fmt+args is subjected to four tests: Three where we * tell vsnprintf varying buffer sizes (plenty, not quite * enough and 0), and then we also test that kvasprintf would * be able to print it as expected. */ I don't see why one would need to do anything special for %pD. Rasmus
> -----Original Message----- > From: Rasmus Villemoes <linux@rasmusvillemoes.dk> > Sent: Tuesday, June 15, 2021 3:48 PM > To: Justin He <Justin.He@arm.com>; Petr Mladek <pmladek@suse.com> > Cc: Steven Rostedt <rostedt@goodmis.org>; Sergey Senozhatsky > <senozhatsky@chromium.org>; Andy Shevchenko > <andriy.shevchenko@linux.intel.com>; Jonathan Corbet <corbet@lwn.net>; > Alexander Viro <viro@zeniv.linux.org.uk>; Linus Torvalds <torvalds@linux- > foundation.org>; Peter Zijlstra (Intel) <peterz@infradead.org>; Eric > Biggers <ebiggers@google.com>; Ahmed S. Darwish <a.darwish@linutronix.de>; > linux-doc@vger.kernel.org; linux-kernel@vger.kernel.org; linux- > fsdevel@vger.kernel.org > Subject: Re: [PATCH RFCv3 3/3] lib/test_printf: add test cases for '%pD' > > On 15/06/2021 09.07, Justin He wrote: > > Hi Petr > > > > >>> +static void __init > >>> +f_d_path(void) > >>> +{ > >>> + test("(null)", "%pD", NULL); > >>> + test("(efault)", "%pD", PTR_INVALID); > >>> + > >>> + is_prepend_buf = true; > >>> + test("/bravo/alfa |/bravo/alfa ", "%-14pD|%*pD", &test_file, - > 14, > >> &test_file); > >>> + test(" /bravo/alfa| /bravo/alfa", "%14pD|%*pD", &test_file, 14, > >> &test_file); > >>> + test(" /bravo/alfa|/bravo/alfa ", "%14pD|%-14pD", &test_file, > >> &test_file); > >> > >> Please, add more test for scenarios when the path does not fit into > >> the buffer or when there are no limitations, ... > > > > Indeed, thanks > > Doesn't the existing test() helper do this for you automatically? > > /* > * Every fmt+args is subjected to four tests: Three where we > * tell vsnprintf varying buffer sizes (plenty, not quite > * enough and 0), and then we also test that kvasprintf would > * be able to print it as expected. > */ > Yes, it had invoked vsnprintf for 3 times in __test() vsnprintf(buf,256) vsnprintf(buf,random_bytes,...) vsnprintf(buf, 0,...); seems no need to add more test cases > I don't see why one would need to do anything special for %pD. Okay, got it, agree -- Cheers, Justin (Jia He) IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
On Tue, Jun 15, 2021 at 07:56:01AM +0000, Justin He wrote: > > From: Rasmus Villemoes <linux@rasmusvillemoes.dk> > > Sent: Tuesday, June 15, 2021 3:48 PM > > On 15/06/2021 09.07, Justin He wrote: > IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. Just a reminder that you still have this footer that prevents (some) people to respond to your messages.
diff --git a/lib/test_printf.c b/lib/test_printf.c index ec0d5976bb69..3632bd6cf906 100644 --- a/lib/test_printf.c +++ b/lib/test_printf.c @@ -16,6 +16,7 @@ #include <linux/bitmap.h> #include <linux/dcache.h> +#include <linux/fs.h> #include <linux/socket.h> #include <linux/in.h> @@ -34,6 +35,7 @@ KSTM_MODULE_GLOBALS(); static char *test_buffer __initdata; static char *alloced_buffer __initdata; +static bool is_prepend_buf; extern bool no_hash_pointers; @@ -78,7 +80,7 @@ do_test(int bufsize, const char *expect, int elen, return 1; } - if (memchr_inv(test_buffer + written + 1, FILL_CHAR, BUF_SIZE + PAD_SIZE - (written + 1))) { + if (!is_prepend_buf && memchr_inv(test_buffer + written + 1, FILL_CHAR, BUF_SIZE + PAD_SIZE - (written + 1))) { pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote beyond the nul-terminator\n", bufsize, fmt); return 1; @@ -496,6 +498,27 @@ dentry(void) test(" bravo/alfa| bravo/alfa", "%12pd2|%*pd2", &test_dentry[2], 12, &test_dentry[2]); } +static struct vfsmount test_vfsmnt = {}; + +static struct file test_file __initdata = { + .f_path = { .dentry = &test_dentry[2], + .mnt = &test_vfsmnt, + }, +}; + +static void __init +f_d_path(void) +{ + test("(null)", "%pD", NULL); + test("(efault)", "%pD", PTR_INVALID); + + is_prepend_buf = true; + test("/bravo/alfa |/bravo/alfa ", "%-14pD|%*pD", &test_file, -14, &test_file); + test(" /bravo/alfa| /bravo/alfa", "%14pD|%*pD", &test_file, 14, &test_file); + test(" /bravo/alfa|/bravo/alfa ", "%14pD|%-14pD", &test_file, &test_file); + is_prepend_buf = false; +} + static void __init struct_va_format(void) { @@ -779,6 +802,7 @@ test_pointer(void) ip(); uuid(); dentry(); + f_d_path(); struct_va_format(); time_and_date(); struct_clk();
After the behaviour of specifier '%pD' is changed to print full path of struct file, the related test cases are also updated. Given the string is prepended from the end of the buffer, the check of "wrote beyond the nul-terminator" should be skipped. Signed-off-by: Jia He <justin.he@arm.com> --- lib/test_printf.c | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-)