Re: [PATCH v2] tools/hv: Add memory allocation check in hv_fcopy_start
From: Saurabh Singh Sengar <ssengar@linux.microsoft.com>
Date: 2024-09-05 05:20:33
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On Sat, Aug 31, 2024 at 12:34:43AM +0000, Dexuan Cui wrote:
quoted hunk ↗ jump to hunk
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From: Zhu Jun <redacted> Sent: Wednesday, August 28, 2024 7:45 PM@@ -296,6 +296,18 @@ static int hv_fcopy_start(struct hv_start_fcopy*smsg_in) file_name = (char *)malloc(file_size * sizeof(char)); path_name = (char *)malloc(path_size * sizeof(char)); + if (!file_name) { + free(file_name); + syslog(LOG_ERR, "Can't allocate file_name memory!"); + exit(EXIT_FAILURE); + } + + if (!path_name) { + free(path_name); + syslog(LOG_ERR, "Can't allocate path_name memory!"); + exit(EXIT_FAILURE); + }If we're calling exit() just 2 lines later, it doesn't make a lot of sense to call free(). How about this:@@ -296,6 +296,12 @@ static int hv_fcopy_start(struct hv_start_fcopy *smsg_in) file_name = (char *)malloc(file_size * sizeof(char)); path_name = (char *)malloc(path_size * sizeof(char)); + if (!file_name || !path_name) { + free(file_name); + free(path_name); + syslog(LOG_ERR, "Can't allocate memory for file name and/or path name"); + return HV_E_FAIL; + }Note: free(NULL) is valid (refer to "man 3 free").
hv_fcopy_send_data is the parent function which calls hv_fcopy_start. Possibly a good solution is to check the return value from hv_fcopy_send_data in fcopy_pkt_process function. Otherwise I prefer exit over returning error. And as you rightly pointed out if we use exit, there is no sense of using free. - Saurabh