All of lore.kernel.org
 help / color / mirror / Atom feed
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	"J. Bruce Fields" <bfields@fieldses.org>,
	Trond Myklebust <trond.myklebust@primarydata.com>,
	Anna Schumaker <anna.schumaker@netapp.com>,
	"David S. Miller" <davem@davemloft.net>,
	linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org,
	netdev@vger.kernel.org
Subject: Re: [PATCH v4 3/3] lib/string_helpers.c: Change semantics of string_escape_mem
Date: Wed, 04 Mar 2015 13:49:35 +0200	[thread overview]
Message-ID: <1425469775.14897.174.camel@linux.intel.com> (raw)
In-Reply-To: <1425424836-17947-4-git-send-email-linux@rasmusvillemoes.dk>

On Wed, 2015-03-04 at 00:20 +0100, Rasmus Villemoes wrote:
> The current semantics of string_escape_mem are inadequate for one of
> its current users, vsnprintf(). If that is to honour its contract, it
> must know how much space would be needed for the entire escaped
> buffer, and string_escape_mem provides no way of obtaining that (short
> of allocating a large enough buffer (~4 times input string) to let it
> play with, and that's definitely a big no-no inside vsnprintf).
> 
> So change the semantics for string_escape_mem to be more
> snprintf-like: Return the size of the output that would be generated
> if the destination buffer was big enough, but of course still only
> write to the part of dst it is allowed to, and (contrary to snprintf)
> don't do '\0'-termination. It is then up to the caller to detect
> whether output was truncated and to append a '\0' if desired. Also, we
> must output partial escape sequences, otherwise a call such as
> snprintf(buf, 3, "%1pE", "\123") would cause printf to write a \0 to
> buf[2] but leaving buf[0] and buf[1] with whatever they previously
> contained.
> 
> This also fixes a bug in the escaped_string() helper function, which
> used to unconditionally pass a length of "end-buf" to
> string_escape_mem(); since the latter doesn't check osz for being
> insanely large, it would happily write to dst. For example,
> kasprintf(GFP_KERNEL, "something and then %pE", ...); is an easy way
> to trigger an oops.
> 
> In test-string_helpers.c, the -ENOMEM test is replaced with testing
> for getting the expected return value even if the buffer is too
> small. We also ensure that nothing is written (by relying on a NULL
> pointer deref) if the output size is 0 by passing NULL - this has to
> work for kasprintf("%pE") to work.
> 
> In net/sunrpc/cache.c, I think qword_add still has the same
> semantics. Someone should definitely double-check this.
> 
> In fs/proc/array.c, I made the minimum possible change, but
> longer-term it should stop poking around in seq_file internals.
> 
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>

Thanks!

One nitpick below, but anyway
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
for everything except net/sunrpc/cache.c

> ---
>  fs/proc/array.c                |  4 ++--
>  include/linux/string_helpers.h |  8 +++----
>  lib/string_helpers.c           | 49 ++++++------------------------------------
>  lib/test-string_helpers.c      | 40 +++++++++++++++++-----------------
>  lib/vsprintf.c                 |  8 +++++--
>  net/sunrpc/cache.c             |  8 ++++---
>  6 files changed, 44 insertions(+), 73 deletions(-)
> 
> diff --git a/fs/proc/array.c b/fs/proc/array.c
> index 1295a00ca316..b5405889a780 100644
> --- a/fs/proc/array.c
> +++ b/fs/proc/array.c
> @@ -99,8 +99,8 @@ static inline void task_name(struct seq_file *m, struct task_struct *p)
>  	buf = m->buf + m->count;
>  
>  	/* Ignore error for now */
> -	string_escape_str(tcomm, &buf, m->size - m->count,
> -			  ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
> +	buf += string_escape_str(tcomm, buf, m->size - m->count,
> +				 ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
>  
>  	m->count = buf - m->buf;
>  	seq_putc(m, '\n');
> diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
> index 657571817260..0991913f4953 100644
> --- a/include/linux/string_helpers.h
> +++ b/include/linux/string_helpers.h
> @@ -47,22 +47,22 @@ static inline int string_unescape_any_inplace(char *buf)
>  #define ESCAPE_ANY_NP		(ESCAPE_ANY | ESCAPE_NP)
>  #define ESCAPE_HEX		0x20
>  
> -int string_escape_mem(const char *src, size_t isz, char **dst, size_t osz,
> +int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
>  		unsigned int flags, const char *esc);
>  
>  static inline int string_escape_mem_any_np(const char *src, size_t isz,
> -		char **dst, size_t osz, const char *esc)
> +		char *dst, size_t osz, const char *esc)
>  {
>  	return string_escape_mem(src, isz, dst, osz, ESCAPE_ANY_NP, esc);
>  }
>  
> -static inline int string_escape_str(const char *src, char **dst, size_t sz,
> +static inline int string_escape_str(const char *src, char *dst, size_t sz,
>  		unsigned int flags, const char *esc)
>  {
>  	return string_escape_mem(src, strlen(src), dst, sz, flags, esc);
>  }
>  
> -static inline int string_escape_str_any_np(const char *src, char **dst,
> +static inline int string_escape_str_any_np(const char *src, char *dst,
>  		size_t sz, const char *esc)
>  {
>  	return string_escape_str(src, dst, sz, ESCAPE_ANY_NP, esc);
> diff --git a/lib/string_helpers.c b/lib/string_helpers.c
> index 9c48ddad0f0d..1826c7407258 100644
> --- a/lib/string_helpers.c
> +++ b/lib/string_helpers.c
> @@ -274,11 +274,6 @@ static bool escape_space(unsigned char c, char **dst, char *end)
>  		return false;
>  	}
>  
> -	if (out + 2 > end) {
> -		*dst = out + 2;
> -		return true;
> -	}
> -
>  	if (out < end)
>  		*out = '\\';
>  	++out;
> @@ -309,11 +304,6 @@ static bool escape_special(unsigned char c, char **dst, char *end)
>  		return false;
>  	}
>  
> -	if (out + 2 > end) {
> -		*dst = out + 2;
> -		return true;
> -	}
> -
>  	if (out < end)
>  		*out = '\\';
>  	++out;
> @@ -332,11 +322,6 @@ static bool escape_null(unsigned char c, char **dst, char *end)
>  	if (c)
>  		return false;
>  
> -	if (out + 2 > end) {
> -		*dst = out + 2;
> -		return true;
> -	}
> -
>  	if (out < end)
>  		*out = '\\';
>  	++out;
> @@ -352,11 +337,6 @@ static bool escape_octal(unsigned char c, char **dst, char *end)
>  {
>  	char *out = *dst;
>  
> -	if (out + 4 > end) {
> -		*dst = out + 4;
> -		return true;
> -	}
> -
>  	if (out < end)
>  		*out = '\\';
>  	++out;
> @@ -378,11 +358,6 @@ static bool escape_hex(unsigned char c, char **dst, char *end)
>  {
>  	char *out = *dst;
>  
> -	if (out + 4 > end) {
> -		*dst = out + 4;
> -		return true;
> -	}
> -
>  	if (out < end)
>  		*out = '\\';
>  	++out;
> @@ -449,20 +424,17 @@ static bool escape_hex(unsigned char c, char **dst, char *end)
>   * it if needs.
>   *
>   * Return:
> - * The amount of the characters processed to the destination buffer, or
> - * %-ENOMEM if the size of buffer is not enough to put an escaped character is
> - * returned.
> - *
> - * Even in the case of error @dst pointer will be updated to point to the byte
> - * after the last processed character.
> + * The total size of the escaped output that would be generated for
> + * the given input and flags. To check whether the output was
> + * truncated, compare the return value to osz. There is room left in
> + * dst for a '\0' terminator if and only if ret < osz.
>   */
> -int string_escape_mem(const char *src, size_t isz, char **dst, size_t osz,
> +int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
>  		      unsigned int flags, const char *esc)
>  {
> -	char *p = *dst;
> +	char *p = dst;
>  	char *end = p + osz;
>  	bool is_dict = esc && *esc;
> -	int ret;
>  
>  	while (isz--) {
>  		unsigned char c = *src++;
> @@ -502,13 +474,6 @@ int string_escape_mem(const char *src, size_t isz, char **dst, size_t osz,
>  		escape_passthrough(c, &p, end);
>  	}
>  
> -	if (p > end) {
> -		*dst = end;
> -		return -ENOMEM;
> -	}
> -
> -	ret = p - *dst;
> -	*dst = p;
> -	return ret;
> +	return p - dst;
>  }
>  EXPORT_SYMBOL(string_escape_mem);
> diff --git a/lib/test-string_helpers.c b/lib/test-string_helpers.c
> index ab0d30e1e18f..8e376efd88a4 100644
> --- a/lib/test-string_helpers.c
> +++ b/lib/test-string_helpers.c
> @@ -260,16 +260,28 @@ static __init const char *test_string_find_match(const struct test_string_2 *s2,
>  	return NULL;
>  }
>  
> +static __init void
> +test_string_escape_overflow(const char *in, int p, unsigned int flags, const char *esc,
> +			    int q_test, const char *name)

Just a nitpick. Can we reformat this to have return type and name on one
line?

> +{
> +	int q_real;
> +
> +	q_real = string_escape_mem(in, p, NULL, 0, flags, esc);
> +	if (q_real != q_test)
> +		pr_warn("Test '%s' failed: flags = %u, osz = 0, expected %d, got %d\n",
> +			name, flags, q_test, q_real);
> +}
> +
>  static __init void test_string_escape(const char *name,
>  				      const struct test_string_2 *s2,
>  				      unsigned int flags, const char *esc)
>  {
> -	int q_real = 512;
> -	char *out_test = kmalloc(q_real, GFP_KERNEL);
> -	char *out_real = kmalloc(q_real, GFP_KERNEL);
> +	size_t out_size = 512;
> +	char *out_test = kmalloc(out_size, GFP_KERNEL);
> +	char *out_real = kmalloc(out_size, GFP_KERNEL);
>  	char *in = kmalloc(256, GFP_KERNEL);
> -	char *buf = out_real;
>  	int p = 0, q_test = 0;
> +	int q_real;
>  
>  	if (!out_test || !out_real || !in)
>  		goto out;
> @@ -301,29 +313,19 @@ static __init void test_string_escape(const char *name,
>  		q_test += len;
>  	}
>  
> -	q_real = string_escape_mem(in, p, &buf, q_real, flags, esc);
> +	q_real = string_escape_mem(in, p, out_real, out_size, flags, esc);
>  
>  	test_string_check_buf(name, flags, in, p, out_real, q_real, out_test,
>  			      q_test);
> +
> +	test_string_escape_overflow(in, p, flags, esc, q_test, name);
> +
>  out:
>  	kfree(in);
>  	kfree(out_real);
>  	kfree(out_test);
>  }
>  
> -static __init void test_string_escape_nomem(void)
> -{
> -	char *in = "\eb \\C\007\"\x90\r]";
> -	char out[64], *buf = out;
> -	int rc = -ENOMEM, ret;
> -
> -	ret = string_escape_str_any_np(in, &buf, strlen(in), NULL);
> -	if (ret == rc)
> -		return;
> -
> -	pr_err("Test 'escape nomem' failed: got %d instead of %d\n", ret, rc);
> -}
> -
>  static int __init test_string_helpers_init(void)
>  {
>  	unsigned int i;
> @@ -342,8 +344,6 @@ static int __init test_string_helpers_init(void)
>  	for (i = 0; i < (ESCAPE_ANY_NP | ESCAPE_HEX) + 1; i++)
>  		test_string_escape("escape 1", escape1, i, TEST_STRING_2_DICT_1);
>  
> -	test_string_escape_nomem();
> -
>  	return -EINVAL;
>  }
>  module_init(test_string_helpers_init);
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index a1b6487c6710..9651686f3b42 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -1241,8 +1241,12 @@ char *escaped_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
>  
>  	len = spec.field_width < 0 ? 1 : spec.field_width;
>  
> -	/* Ignore the error. We print as many characters as we can */
> -	string_escape_mem(addr, len, &buf, end - buf, flags, NULL);
> +	/*
> +	 * string_escape_mem() writes as many characters as it can to
> +	 * the given buffer, and returns the total size of the output
> +	 * had the buffer been big enough.
> +	 */
> +	buf += string_escape_mem(addr, len, buf, buf < end ? end - buf : 0, flags, NULL);
>  
>  	return buf;
>  }
> diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
> index 33fb105d4352..22c4418057f4 100644
> --- a/net/sunrpc/cache.c
> +++ b/net/sunrpc/cache.c
> @@ -1068,12 +1068,14 @@ void qword_add(char **bpp, int *lp, char *str)
>  {
>  	char *bp = *bpp;
>  	int len = *lp;
> -	int ret;
> +	int ret, written;
>  
>  	if (len < 0) return;
>  
> -	ret = string_escape_str(str, &bp, len, ESCAPE_OCTAL, "\\ \n\t");
> -	if (ret < 0 || ret == len)
> +	ret = string_escape_str(str, bp, len, ESCAPE_OCTAL, "\\ \n\t");
> +	written = min(ret, len);
> +	bp += written;

Do we need extra variable?

> +	if (ret >= len)

Something already done in the min.

>  		len = -1;
>  	else {
>  		len -= ret;

Would we simplify this?
 
ret = string_escape_str(str, bp, len, ESCAPE_OCTAL, "\\ \n\t");
if (ret >= len) {
 bp += len;
 len = -1;
} else {
 bp += ret;
…


-- 
Andy Shevchenko <andriy.shevchenko@intel.com>
Intel Finland Oy


WARNING: multiple messages have this Message-ID
From: Andy Shevchenko <andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
To: Rasmus Villemoes
	<linux-qQsb+v5E8BnlAoU/VqSP6n9LOBIZ5rWg@public.gmane.org>
Cc: Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	"J. Bruce Fields"
	<bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>,
	Trond Myklebust
	<trond.myklebust-7I+n7zu2hftEKMMhf/gKZA@public.gmane.org>,
	Anna Schumaker
	<anna.schumaker-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org>,
	"David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH v4 3/3] lib/string_helpers.c: Change semantics of string_escape_mem
Date: Wed, 04 Mar 2015 13:49:35 +0200	[thread overview]
Message-ID: <1425469775.14897.174.camel@linux.intel.com> (raw)
In-Reply-To: <1425424836-17947-4-git-send-email-linux-qQsb+v5E8BnlAoU/VqSP6n9LOBIZ5rWg@public.gmane.org>

On Wed, 2015-03-04 at 00:20 +0100, Rasmus Villemoes wrote:
> The current semantics of string_escape_mem are inadequate for one of
> its current users, vsnprintf(). If that is to honour its contract, it
> must know how much space would be needed for the entire escaped
> buffer, and string_escape_mem provides no way of obtaining that (short
> of allocating a large enough buffer (~4 times input string) to let it
> play with, and that's definitely a big no-no inside vsnprintf).
> 
> So change the semantics for string_escape_mem to be more
> snprintf-like: Return the size of the output that would be generated
> if the destination buffer was big enough, but of course still only
> write to the part of dst it is allowed to, and (contrary to snprintf)
> don't do '\0'-termination. It is then up to the caller to detect
> whether output was truncated and to append a '\0' if desired. Also, we
> must output partial escape sequences, otherwise a call such as
> snprintf(buf, 3, "%1pE", "\123") would cause printf to write a \0 to
> buf[2] but leaving buf[0] and buf[1] with whatever they previously
> contained.
> 
> This also fixes a bug in the escaped_string() helper function, which
> used to unconditionally pass a length of "end-buf" to
> string_escape_mem(); since the latter doesn't check osz for being
> insanely large, it would happily write to dst. For example,
> kasprintf(GFP_KERNEL, "something and then %pE", ...); is an easy way
> to trigger an oops.
> 
> In test-string_helpers.c, the -ENOMEM test is replaced with testing
> for getting the expected return value even if the buffer is too
> small. We also ensure that nothing is written (by relying on a NULL
> pointer deref) if the output size is 0 by passing NULL - this has to
> work for kasprintf("%pE") to work.
> 
> In net/sunrpc/cache.c, I think qword_add still has the same
> semantics. Someone should definitely double-check this.
> 
> In fs/proc/array.c, I made the minimum possible change, but
> longer-term it should stop poking around in seq_file internals.
> 
> Signed-off-by: Rasmus Villemoes <linux-qQsb+v5E8BnlAoU/VqSP6n9LOBIZ5rWg@public.gmane.org>

Thanks!

One nitpick below, but anyway
Acked-by: Andy Shevchenko <andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
for everything except net/sunrpc/cache.c

> ---
>  fs/proc/array.c                |  4 ++--
>  include/linux/string_helpers.h |  8 +++----
>  lib/string_helpers.c           | 49 ++++++------------------------------------
>  lib/test-string_helpers.c      | 40 +++++++++++++++++-----------------
>  lib/vsprintf.c                 |  8 +++++--
>  net/sunrpc/cache.c             |  8 ++++---
>  6 files changed, 44 insertions(+), 73 deletions(-)
> 
> diff --git a/fs/proc/array.c b/fs/proc/array.c
> index 1295a00ca316..b5405889a780 100644
> --- a/fs/proc/array.c
> +++ b/fs/proc/array.c
> @@ -99,8 +99,8 @@ static inline void task_name(struct seq_file *m, struct task_struct *p)
>  	buf = m->buf + m->count;
>  
>  	/* Ignore error for now */
> -	string_escape_str(tcomm, &buf, m->size - m->count,
> -			  ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
> +	buf += string_escape_str(tcomm, buf, m->size - m->count,
> +				 ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
>  
>  	m->count = buf - m->buf;
>  	seq_putc(m, '\n');
> diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
> index 657571817260..0991913f4953 100644
> --- a/include/linux/string_helpers.h
> +++ b/include/linux/string_helpers.h
> @@ -47,22 +47,22 @@ static inline int string_unescape_any_inplace(char *buf)
>  #define ESCAPE_ANY_NP		(ESCAPE_ANY | ESCAPE_NP)
>  #define ESCAPE_HEX		0x20
>  
> -int string_escape_mem(const char *src, size_t isz, char **dst, size_t osz,
> +int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
>  		unsigned int flags, const char *esc);
>  
>  static inline int string_escape_mem_any_np(const char *src, size_t isz,
> -		char **dst, size_t osz, const char *esc)
> +		char *dst, size_t osz, const char *esc)
>  {
>  	return string_escape_mem(src, isz, dst, osz, ESCAPE_ANY_NP, esc);
>  }
>  
> -static inline int string_escape_str(const char *src, char **dst, size_t sz,
> +static inline int string_escape_str(const char *src, char *dst, size_t sz,
>  		unsigned int flags, const char *esc)
>  {
>  	return string_escape_mem(src, strlen(src), dst, sz, flags, esc);
>  }
>  
> -static inline int string_escape_str_any_np(const char *src, char **dst,
> +static inline int string_escape_str_any_np(const char *src, char *dst,
>  		size_t sz, const char *esc)
>  {
>  	return string_escape_str(src, dst, sz, ESCAPE_ANY_NP, esc);
> diff --git a/lib/string_helpers.c b/lib/string_helpers.c
> index 9c48ddad0f0d..1826c7407258 100644
> --- a/lib/string_helpers.c
> +++ b/lib/string_helpers.c
> @@ -274,11 +274,6 @@ static bool escape_space(unsigned char c, char **dst, char *end)
>  		return false;
>  	}
>  
> -	if (out + 2 > end) {
> -		*dst = out + 2;
> -		return true;
> -	}
> -
>  	if (out < end)
>  		*out = '\\';
>  	++out;
> @@ -309,11 +304,6 @@ static bool escape_special(unsigned char c, char **dst, char *end)
>  		return false;
>  	}
>  
> -	if (out + 2 > end) {
> -		*dst = out + 2;
> -		return true;
> -	}
> -
>  	if (out < end)
>  		*out = '\\';
>  	++out;
> @@ -332,11 +322,6 @@ static bool escape_null(unsigned char c, char **dst, char *end)
>  	if (c)
>  		return false;
>  
> -	if (out + 2 > end) {
> -		*dst = out + 2;
> -		return true;
> -	}
> -
>  	if (out < end)
>  		*out = '\\';
>  	++out;
> @@ -352,11 +337,6 @@ static bool escape_octal(unsigned char c, char **dst, char *end)
>  {
>  	char *out = *dst;
>  
> -	if (out + 4 > end) {
> -		*dst = out + 4;
> -		return true;
> -	}
> -
>  	if (out < end)
>  		*out = '\\';
>  	++out;
> @@ -378,11 +358,6 @@ static bool escape_hex(unsigned char c, char **dst, char *end)
>  {
>  	char *out = *dst;
>  
> -	if (out + 4 > end) {
> -		*dst = out + 4;
> -		return true;
> -	}
> -
>  	if (out < end)
>  		*out = '\\';
>  	++out;
> @@ -449,20 +424,17 @@ static bool escape_hex(unsigned char c, char **dst, char *end)
>   * it if needs.
>   *
>   * Return:
> - * The amount of the characters processed to the destination buffer, or
> - * %-ENOMEM if the size of buffer is not enough to put an escaped character is
> - * returned.
> - *
> - * Even in the case of error @dst pointer will be updated to point to the byte
> - * after the last processed character.
> + * The total size of the escaped output that would be generated for
> + * the given input and flags. To check whether the output was
> + * truncated, compare the return value to osz. There is room left in
> + * dst for a '\0' terminator if and only if ret < osz.
>   */
> -int string_escape_mem(const char *src, size_t isz, char **dst, size_t osz,
> +int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
>  		      unsigned int flags, const char *esc)
>  {
> -	char *p = *dst;
> +	char *p = dst;
>  	char *end = p + osz;
>  	bool is_dict = esc && *esc;
> -	int ret;
>  
>  	while (isz--) {
>  		unsigned char c = *src++;
> @@ -502,13 +474,6 @@ int string_escape_mem(const char *src, size_t isz, char **dst, size_t osz,
>  		escape_passthrough(c, &p, end);
>  	}
>  
> -	if (p > end) {
> -		*dst = end;
> -		return -ENOMEM;
> -	}
> -
> -	ret = p - *dst;
> -	*dst = p;
> -	return ret;
> +	return p - dst;
>  }
>  EXPORT_SYMBOL(string_escape_mem);
> diff --git a/lib/test-string_helpers.c b/lib/test-string_helpers.c
> index ab0d30e1e18f..8e376efd88a4 100644
> --- a/lib/test-string_helpers.c
> +++ b/lib/test-string_helpers.c
> @@ -260,16 +260,28 @@ static __init const char *test_string_find_match(const struct test_string_2 *s2,
>  	return NULL;
>  }
>  
> +static __init void
> +test_string_escape_overflow(const char *in, int p, unsigned int flags, const char *esc,
> +			    int q_test, const char *name)

Just a nitpick. Can we reformat this to have return type and name on one
line?

> +{
> +	int q_real;
> +
> +	q_real = string_escape_mem(in, p, NULL, 0, flags, esc);
> +	if (q_real != q_test)
> +		pr_warn("Test '%s' failed: flags = %u, osz = 0, expected %d, got %d\n",
> +			name, flags, q_test, q_real);
> +}
> +
>  static __init void test_string_escape(const char *name,
>  				      const struct test_string_2 *s2,
>  				      unsigned int flags, const char *esc)
>  {
> -	int q_real = 512;
> -	char *out_test = kmalloc(q_real, GFP_KERNEL);
> -	char *out_real = kmalloc(q_real, GFP_KERNEL);
> +	size_t out_size = 512;
> +	char *out_test = kmalloc(out_size, GFP_KERNEL);
> +	char *out_real = kmalloc(out_size, GFP_KERNEL);
>  	char *in = kmalloc(256, GFP_KERNEL);
> -	char *buf = out_real;
>  	int p = 0, q_test = 0;
> +	int q_real;
>  
>  	if (!out_test || !out_real || !in)
>  		goto out;
> @@ -301,29 +313,19 @@ static __init void test_string_escape(const char *name,
>  		q_test += len;
>  	}
>  
> -	q_real = string_escape_mem(in, p, &buf, q_real, flags, esc);
> +	q_real = string_escape_mem(in, p, out_real, out_size, flags, esc);
>  
>  	test_string_check_buf(name, flags, in, p, out_real, q_real, out_test,
>  			      q_test);
> +
> +	test_string_escape_overflow(in, p, flags, esc, q_test, name);
> +
>  out:
>  	kfree(in);
>  	kfree(out_real);
>  	kfree(out_test);
>  }
>  
> -static __init void test_string_escape_nomem(void)
> -{
> -	char *in = "\eb \\C\007\"\x90\r]";
> -	char out[64], *buf = out;
> -	int rc = -ENOMEM, ret;
> -
> -	ret = string_escape_str_any_np(in, &buf, strlen(in), NULL);
> -	if (ret == rc)
> -		return;
> -
> -	pr_err("Test 'escape nomem' failed: got %d instead of %d\n", ret, rc);
> -}
> -
>  static int __init test_string_helpers_init(void)
>  {
>  	unsigned int i;
> @@ -342,8 +344,6 @@ static int __init test_string_helpers_init(void)
>  	for (i = 0; i < (ESCAPE_ANY_NP | ESCAPE_HEX) + 1; i++)
>  		test_string_escape("escape 1", escape1, i, TEST_STRING_2_DICT_1);
>  
> -	test_string_escape_nomem();
> -
>  	return -EINVAL;
>  }
>  module_init(test_string_helpers_init);
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index a1b6487c6710..9651686f3b42 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -1241,8 +1241,12 @@ char *escaped_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
>  
>  	len = spec.field_width < 0 ? 1 : spec.field_width;
>  
> -	/* Ignore the error. We print as many characters as we can */
> -	string_escape_mem(addr, len, &buf, end - buf, flags, NULL);
> +	/*
> +	 * string_escape_mem() writes as many characters as it can to
> +	 * the given buffer, and returns the total size of the output
> +	 * had the buffer been big enough.
> +	 */
> +	buf += string_escape_mem(addr, len, buf, buf < end ? end - buf : 0, flags, NULL);
>  
>  	return buf;
>  }
> diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
> index 33fb105d4352..22c4418057f4 100644
> --- a/net/sunrpc/cache.c
> +++ b/net/sunrpc/cache.c
> @@ -1068,12 +1068,14 @@ void qword_add(char **bpp, int *lp, char *str)
>  {
>  	char *bp = *bpp;
>  	int len = *lp;
> -	int ret;
> +	int ret, written;
>  
>  	if (len < 0) return;
>  
> -	ret = string_escape_str(str, &bp, len, ESCAPE_OCTAL, "\\ \n\t");
> -	if (ret < 0 || ret == len)
> +	ret = string_escape_str(str, bp, len, ESCAPE_OCTAL, "\\ \n\t");
> +	written = min(ret, len);
> +	bp += written;

Do we need extra variable?

> +	if (ret >= len)

Something already done in the min.

>  		len = -1;
>  	else {
>  		len -= ret;

Would we simplify this?
 
ret = string_escape_str(str, bp, len, ESCAPE_OCTAL, "\\ \n\t");
if (ret >= len) {
 bp += len;
 len = -1;
} else {
 bp += ret;
…


-- 
Andy Shevchenko <andriy.shevchenko-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Intel Finland Oy

--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

  reply	other threads:[~2015-03-04 11:49 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-28 13:25 [PATCH 0/2] Two printf fixes Rasmus Villemoes
2015-01-28 13:25 ` [PATCH 1/2] lib/vsprintf.c: Fix potential NULL deref in hex_string Rasmus Villemoes
2015-01-28 14:53   ` Andy Shevchenko
2015-01-28 15:49     ` Rasmus Villemoes
2015-01-28 16:43       ` Andy Shevchenko
2015-01-28 13:25 ` [PATCH 2/2] string_helpers: Change semantics of string_escape_mem Rasmus Villemoes
2015-01-28 15:05   ` Andy Shevchenko
2015-01-29 10:03 ` [PATCH v2 0/3] Two printf fixes Rasmus Villemoes
2015-01-29 10:03   ` [PATCH v2 1/3] lib/vsprintf.c: Fix potential NULL deref in hex_string Rasmus Villemoes
2015-01-29 10:43     ` Andy Shevchenko
2015-01-29 10:03   ` [PATCH v2 2/3] lib/string_helpers.c: Refactor string_escape_mem Rasmus Villemoes
2015-01-29 12:12     ` Andy Shevchenko
2015-01-29 13:10       ` Rasmus Villemoes
2015-01-29 13:37         ` Andy Shevchenko
2015-01-29 19:33           ` Jeff Epler
2015-01-30 10:14             ` Andy Shevchenko
2015-01-29 10:03   ` [PATCH v2 3/3] lib/string_helpers.c: Change semantics of string_escape_mem Rasmus Villemoes
2015-01-29 13:29     ` Andy Shevchenko
2015-01-29 14:29       ` Rasmus Villemoes
2015-01-30 10:27         ` Andy Shevchenko
2015-01-30 23:39           ` Rasmus Villemoes
2015-01-30 23:39             ` Rasmus Villemoes
2015-02-02 10:56             ` Andy Shevchenko
2015-02-09 23:44   ` [PATCH v3 0/3] Two printf fixes Rasmus Villemoes
2015-02-09 23:44     ` Rasmus Villemoes
2015-02-09 23:44     ` [PATCH v3 1/3] lib/vsprintf.c: Fix potential NULL deref in hex_string Rasmus Villemoes
2015-02-09 23:44     ` [PATCH v3 2/3] lib/string_helpers.c: Refactor string_escape_mem Rasmus Villemoes
2015-02-10 12:16       ` Andy Shevchenko
2015-02-09 23:44     ` [PATCH v3 3/3] lib/string_helpers.c: Change semantics of string_escape_mem Rasmus Villemoes
2015-02-09 23:44       ` Rasmus Villemoes
2015-02-10 12:32       ` Andy Shevchenko
2015-02-10 12:32         ` Andy Shevchenko
2015-02-10 13:02         ` Rasmus Villemoes
2015-02-10 14:22           ` Andy Shevchenko
2015-02-10 14:22             ` Andy Shevchenko
2015-02-21  1:35             ` Rasmus Villemoes
2015-02-23 12:50               ` Andy Shevchenko
2015-02-23 12:50                 ` Andy Shevchenko
2015-02-23 22:55                 ` Rasmus Villemoes
2015-02-23 22:55                   ` Rasmus Villemoes
2015-03-02 12:37                   ` Andy Shevchenko
2015-03-02 12:37                     ` Andy Shevchenko
2015-03-02 23:03                     ` Rasmus Villemoes
2015-03-03 10:26                       ` Andy Shevchenko
2015-03-03 10:26                         ` Andy Shevchenko
2015-03-03 23:20     ` [PATCH v4 0/3] Two printf fixes Rasmus Villemoes
2015-03-03 23:20       ` [PATCH v4 1/3] lib/vsprintf.c: Fix potential NULL deref in hex_string Rasmus Villemoes
2015-03-03 23:20       ` [PATCH v4 2/3] lib/string_helpers.c: Refactor string_escape_mem Rasmus Villemoes
2015-03-04 10:51         ` Andy Shevchenko
2015-03-03 23:20       ` [PATCH v4 3/3] lib/string_helpers.c: Change semantics of string_escape_mem Rasmus Villemoes
2015-03-04 11:49         ` Andy Shevchenko [this message]
2015-03-04 11:49           ` Andy Shevchenko

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1425469775.14897.174.camel@linux.intel.com \
    --to=andriy.shevchenko@linux.intel.com \
    --cc=akpm@linux-foundation.org \
    --cc=anna.schumaker@netapp.com \
    --cc=bfields@fieldses.org \
    --cc=davem@davemloft.net \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-nfs@vger.kernel.org \
    --cc=linux@rasmusvillemoes.dk \
    --cc=netdev@vger.kernel.org \
    --cc=trond.myklebust@primarydata.com \
    --subject='Re: [PATCH v4 3/3] lib/string_helpers.c: Change semantics of string_escape_mem' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.