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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Chris Coulson <chris.coulson@canonical.com>
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Date: Wed, 18 Nov 2020 00:59:24 +0000
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Subject: [PATCH] kern/parser: Fix a memory leak
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The getline() function supplied to grub_parser_split_cmdline() returns
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a newly allocated buffer and can be called multiple times, but the
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returned buffer is never freed.
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Signed-off-by: Chris Coulson <chris.coulson@canonical.com>
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Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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---
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 grub-core/kern/parser.c | 20 ++++++++++++++++----
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 1 file changed, 16 insertions(+), 4 deletions(-)
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diff --git a/grub-core/kern/parser.c b/grub-core/kern/parser.c
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index 94e8728d59a..23ebebf5ffa 100644
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--- a/grub-core/kern/parser.c
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+++ b/grub-core/kern/parser.c
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@@ -140,6 +140,7 @@ grub_parser_split_cmdline (const char *cmdline,
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   char buffer[1024];
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   char *bp = buffer;
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   char *rd = (char *) cmdline;
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+  char *rp = rd;
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   char varname[200];
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   char *vp = varname;
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   char *args;
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@@ -149,10 +150,18 @@ grub_parser_split_cmdline (const char *cmdline,
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   *argv = NULL;
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   do
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     {
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-      if (!rd || !*rd)
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+      if (rp == NULL || *rp == '\0')
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 	{
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+	  if (rd != cmdline)
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+	    {
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+	      grub_free (rd);
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+	      rd = rp = NULL;
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+	    }
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 	  if (getline)
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-	    getline (&rd, 1, getline_data);
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+	    {
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+	      getline (&rd, 1, getline_data);
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+	      rp = rd;
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+	    }
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 	  else
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 	    break;
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 	}
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@@ -160,12 +169,12 @@ grub_parser_split_cmdline (const char *cmdline,
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       if (!rd)
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 	break;
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-      for (; *rd; rd++)
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+      for (; *rp != '\0'; rp++)
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 	{
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 	  grub_parser_state_t newstate;
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 	  char use;
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-	  newstate = grub_parser_cmdline_state (state, *rd, &use;;
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+	  newstate = grub_parser_cmdline_state (state, *rp, &use;;
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 	  /* If a variable was being processed and this character does
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 	     not describe the variable anymore, write the variable to
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@@ -198,6 +207,9 @@ grub_parser_split_cmdline (const char *cmdline,
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     }
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   while (state != GRUB_PARSER_STATE_TEXT && !check_varstate (state));
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+  if (rd != cmdline)
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+    grub_free (rd);
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+
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   /* A special case for when the last character was part of a
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      variable.  */
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   add_var (varname, &bp, &vp, state, GRUB_PARSER_STATE_TEXT);