Subject: [PATCH v5 0/2] Replace atoi() with strtoi_with_tail()

From: "Mohit Marathe via GitGitGadget" <[email-masked]>
Date: Sun, 28 Jan 2024 04:42:30 +0000

Hello,

This patch series replaces atoi() with an updated version of strtol_i()
called strtoi_with_tail (Credits: Junio C Hamano). The reasoning behind this
is to improve error handling by not allowing non-numerical characters in the
hunk header (which might happen in case of a corrupt patch, although
rarely).

There is still a change to be made, as Junio says: "A corrupt patch may be
getting a nonsense patch-ID with the current code and hopefully is not
matching other patches that are not corrupt, but with such a change, a
corrupt patch may not be getting any patch-ID and a loop that computes
patch-ID for many files and try to match them up might need to be rewritten
to take the new failure case into account." I'm not sure where this change
needs to me made (maybe get_one_patchid()?). It would be great if anyone
could point me to the correct place.

Thanks, Mohit Marathe

Mohit Marathe (2):
  git-compat-util: add strtoi_with_tail()
  patch-id: replace `atoi()` with `strtoi_with_tail`

 builtin/patch-id.c | 12 ++++++++----
 git-compat-util.h  | 23 +++++++++++++++++++++++
 2 files changed, 31 insertions(+), 4 deletions(-)

base-commit: b50a608ba20348cb3dfc16a696816d51780e3f0f
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1646%2Fmohit-marathe%2Fupdate-strtol_i-v5
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1646/mohit-marathe/update-strtol_i-v5
Pull-Request: https://github.com/gitgitgadget/git/pull/1646

Range-diff vs v4:

 1:  60ea85a701a ! 1:  f09b0838f04 git-compat-util: add strtol_i_updated()
     @@ Metadata
      Author: Mohit Marathe <[email-masked]>
      
       ## Commit message ##
     -    git-compat-util: add strtol_i_updated()
     +    git-compat-util: add strtoi_with_tail()
      
          This function is an updated version of strtol_i() function. It will
          give more control to handle parsing of the characters after the
     -    integer and better error handling while parsing numbers.
     +    numbers and better error handling while parsing numbers.
      
          Signed-off-by: Mohit Marathe <[email-masked]>
      
     @@ git-compat-util.h: static inline int strtol_i(char const *s, int base, int *resu
       	return 0;
       }
       
     -+#define strtol_i(s,b,r) strtol_i_updated((s), (b), (r), NULL)
     -+static inline int strtol_i_updated(char const *s, int base, int *result, char **endp)
     ++#define strtol_i(s,b,r) strtoi_with_tail((s), (b), (r), NULL)
     ++static inline int strtoi_with_tail(char const *s, int base, int *result, char **endp)
      +{
      +	long ul;
      +	char *dummy = NULL;
 2:  17f2dda4907 ! 2:  ee8f4ae991d patch-id: replace `atoi()` with `strtol_i_updated()`
     @@ Metadata
      Author: Mohit Marathe <[email-masked]>
      
       ## Commit message ##
     -    patch-id: replace `atoi()` with `strtol_i_updated()`
     +    patch-id: replace `atoi()` with `strtoi_with_tail`
      
          The change is made to improve the error-handling capabilities
     -    during the conversion of string representations to integers.
     -    The `strtol_i_updated(` function offers a more robust mechanism for
     +    during the conversion of string to integers. The
     +    `strtoi_with_tail` function offers a more robust mechanism for
          converting strings to integers by providing enhanced error
     -    detection. Unlike `atoi(`, `strtol_i_updated(` allows the code to
     +    detection. Unlike `atoi`, `strtoi_with_tail` allows the code to
          differentiate between a valid conversion and an invalid one,
          offering better resilience against potential issues such as
          reading hunk header of a corrupted patch.
     @@ builtin/patch-id.c: static int scan_hunk_header(const char *p, int *p_before, in
       	if (q[n] == ',') {
       		q += n + 1;
      -		*p_before = atoi(q);
     -+		if (strtol_i_updated(q, 10, p_before, &endp) != 0)
     -+			return 0;
     - 		n = strspn(q, digits);
     -+		if (endp != q + n)
     +-		n = strspn(q, digits);
     ++		if (strtoi_with_tail(q, 10, p_before, &endp) != 0)
      +			return 0;
     ++		n = endp - q;
       	} else {
       		*p_before = 1;
       	}
     @@ builtin/patch-id.c: static int scan_hunk_header(const char *p, int *p_before, in
       	if (r[n] == ',') {
       		r += n + 1;
      -		*p_after = atoi(r);
     -+		if (strtol_i_updated(r, 10, p_after, &endp) != 0)
     -+			return 0;
     - 		n = strspn(r, digits);
     -+		if (endp != r + n)
     +-		n = strspn(r, digits);
     ++		if (strtoi_with_tail(r, 10, p_after, &endp) != 0)
      +			return 0;
     ++		n = endp - r;
       	} else {
       		*p_after = 1;
       	}

-- 
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